The problem is that a 60:40 ratio for throughput / endurance (based on Int as the common factor) is completely arbitrary. Try again with 80:20, or 10:90, or 1:99, and you'll end up with quite different results. Who is to say which is correct? More likely, each would be correct for different roles in different fights. 99:1 might be reasonable for tank healing on Hodir hard-mode, where it's all but impossible to go OOM.

There's no easy way to relate throughput to endurance.

Personally, I'm using roughly 15:85 ratio using your baseline calculations of throughput and endurance. 1 SP : 1.3 Int. I don't think I have any mathematical basis for this; it just *feels* right for most fights.

I've have been using a 50:50 statweight with a bumped up version of spirit (because spirit is better than that statweight with my intellect):

100 SP
100 MP5
74 Intellect
59 Haste
48 Crit
38 Spirit

I would suggest to use sustained hps and peak hps instead of longevity and throughput.

Sustained hps is the hps you can sustain without gooing oom in a given fight length (10 minutes if you want a very fair margin). Basically, it will benefit from all regen stats, but also spellpower and crit (as they increases your heals without increasing the mana cost).
Peak hps is the maximum throughput you can achieve, without considering mana questions. It benefits from all throughput stats, with a great weight on haste.

One advantage is that both consider healing done, which is the metric we usely consider (even if it's not the best one). "Mana saved / regen" is not healing done. In other words, we are adding apples and apples. When we have enough mana to spam all time, both are equivalent... The second advantage is that it models quite well fights with burst healing : you need some higher througput at some times, then you are back to a lower healing phase, and repeat. Peak hps deals with the aoe / high damage phases, and sustained hps with the fact that you need mana for the whole fight.

It's main difficulty is that it's obviously dependent on the fight length...

This is more or less exactly what I do in Rawr. If you use the Custom Rotation in Rawr you can also specify what spells you are using.

The weighted average would work, if you had absolute values or comparable ratios.

However, these ratios are not comparable.

Assume you use the Int-based ratios where the relative value of Int is 1.0 for both longevity and throughput. In that case, though you assign a value of 1.0 to each, 10 points of Int do not have the same absolute value regarding longevity and throughput.

This is why it doesn't work.

Several spells are still not capped even with full raidbuffs and 7% from gear as Disc with Borrowed Time. Penance and Prayer of Healing are the big ones. If you wish to Optimize your gear, you should simply put in a restraint in the Optimizer to not go beyond your wanted Haste value. Like, setting Haste % <= 7.

Beyond that, I'm not sure what to tell you. Personally I prefer having around 10% haste from gear, as it (combined with my latency) Guarantees I get to cast every GCD. And it benefits ProH/Penance, perhaps an occational GHeal, and sometimes, you may not even have 5% spell haste from totem or similar. (10 man.)

Fair enough. However, The Doctor somehow got to those 60/40 values -- I still can't figure out how.

I don't want to turn this into a rawr discussion, but wouldn't that make Haste be "bad" beyond 7% instead of just useless? I'll post something over on the rawr boards so I don't derail this.

Ah, I see now -- I knew I was missing something. Thanks, that helps a lot.

Ignore. I misread something.

The 60/40 value was a very arbitrary ratio. I actually don't use the values from it personally and as I have stated previously don't recommend trying to come up with a combined value. The numbers provided were a "close enough" for those that aren't looking to maximize gear for each circumstance.

Realistically what you should know is how valuable stats are for throughput and for longevity. Then how/why each stat is valuable which is specifically true for comparing crit vs. haste. At that point you can set your gear up optimally for each fight and role. For example if you are tossing out a lot of PW:S primarily to mitigate raid damage and don't use other heals for any significant portion of you healing then you care about getting to the BT'd haste cap, stacking SP, having enough longevity for the length of the fight. That scenario crit is of little to no value because it doesn't help PW:S.

The valuation of the stats outside of the ratio are based on my spreadsheet. If you look at throughput for example you can find the hidden page that calculates how each stat impacts the current healing for a specific spell. Then the spells are weighted on a provided value for what % of casts you use that spell. This is then combined into a net value for each stat... These values change as gear changes, spell composition changes, ..etc.

Looking at the whole stat weighting discussion the first thing I do is ignore int/stam/spellpower these are close to a constant based on iLevel and slot. This leaves spirit, haste, crit and MP5 as the only stats you actually have to consider. Now with Crit beyond ~ 30% raid buffed being of dubious utility and Haste beyond 10% suffering the same issue you are basically juggling between MP5 and spirit in most cases. Which one you value more probably has more to do with what your offspec is. If you are disc/shadow you probably don't care which one you take but if you take Holy as your second spec you probably want to favour spirit so your gear does double duty.

As disc what you want is more spellpower but because the SP total is fixed relative to slot and ilevel it's probably what you want to focus on from gems once you hit the crit and haste soft caps. Unlike most healers who suffer significant dimishing returns on SP after ~2k spell power disc priests and shields can always be usefully bigger. If you are below the soft caps what stat you want to focus on is probably going to depend primarily on how your raid takes/heals damage and the relative skill of the players in the raid. Some people will get better return from regen others from Haste to increase throughput or crit to get more Aegis shields on the tank.

Finally I find that stat weighting tools such as rwar are damn near useless for healers because of the tight bounds that they operate within. The fact is that even on the same fight your casting pattern can differ radically from one week to the next because this week the MT warrior is at the dentist and the Bear is tanking the fight today. Thus the only way to truly decide what stat to focus on is to critically review your own healing and focus on the things that you are personally lacking.