I am getting my Legendary Meta next week. When it procs and you give someone a PW:S since it cost 0 mana technically when rapture procs from being fully absorbed does it give back 0 mana or the actual mana cost? So would it be a mana GAIN to cast it when you have LMG proc?
Yes. When you get LMG procs, the goal is to either use 2 PWS or 1 PWS and lvl90 talent (if off CD). It obviously depends on the situation (for example you wouldn't mid spirit shell).