In general it is best to test glyphs for your own gear, and following is probably easiest way to do it:
opt_raid.simcraft
armory=eu,Server,Player
glyphs=conflagrate/incinerate/immolate
actions=flask,type=frost_wyrm/food,type=tender_shoveltusk_steak/fire_stone/fel_armor/summon_pet,imp
actions+=/curse_of_doom,time_to_die>=90/immolate/conflagrate/chaos_bolt/incinerate/life_tap
Then change to "glyphs=conflagrate/incinerate/imp" and "glyphs=conflagrate/incinerate/life_tap". Of course, to really benefit from LT glyph, actions need to be changed to refresh buff, something along:
opt_raid.simcraft
armory=eu,Server,Player
glyphs=conflagrate/incinerate/life_tap
actions=flask,type=frost_wyrm/food,type=tender_shoveltusk_steak/fire_stone/fel_armor/summon_pet,imp
actions+=/curse_of_doom,time_to_die>=90/life_tap,if=!buffs.life_tap_glyph&mana_perc<90
actions+=/immolate/conflagrate/chaos_bolt/incinerate/life_tap
Above actions will use LT to refresh only when buff is not already up and mana is below 90%. Testing for mana reduce importance of placing LT refresh at start or before incinerate, and increase DPS slightly since GCD wont be wasted for full mana.
Same can be done for BiS warlock of course, just replacing "armory=eu,Server,Player" with "Warlock_T8_00_13_58.simcraft".
BTW, numbers that I got for BiS destro lock:
Immolate glyph: 7918
Imp glyph: 7920
LT with no forced refresh: 7927
LT with refresh: 8010
LT with refresh when mana<90%: 8043