Not sure what's the status on hardmode discussions, but in general, at least the first 3 are quite similar to their normal-mode counterparts. This makes rejuv less dominant than it was in Ulduar, where in nearly every encounter, the entire raid was being blased with AoE at pretty consistent and/or short intervals. It feels like rejuv-blanketing isn't as strong as it used to be, simply on the merits of the encounters themselves. This pushes throughput (=SP) even stronger compared to regen, so gemming with ember might be more viable. Having to maintain a full-red set and a more balanced set, however, will likely deem this option unrealistic, unless you are always comfortable with full SP.
Bhalu - about your trinket, do you use it specifically for Anub? Personally I'm not too fond of SP procs/uses but it seems like for that particular fight it will be beneficial.
[Talisman of Resurgence] is also an interesting option for that fight if you can spare the badges.