Been hearing 385-415 and wondering what is the bast average to aim for rotation and TP manageable levels. ATM running with 419 and during T12 and 13 I have using up alot of TP + burning my invigorate returns before large pauses in the phase change like revived adds in t12 and right before divebombs in 13.
You answered your own question in the post.
If you can make it to your 2nd Invigorate, you are fine on TP. If you can only barely make it to your 2nd Invigorate but someone or a mechanic is guaranteed to take care of your TP before then, you are fine on TP. If you can't make it to your 2nd Invigorate, you should probably drop some (somewhere around 450ish, you will need downtime, a bard, or a ninja). If you keep losing Greased Lightning you feel like you might have saved by split-seconds, you should probably get more (1 SS = ~2.43 ms faster GL3 refresh).
It's a pretty bad stat for dummy tests, but the practical value is subjective and primarily surrounding the above factors. The numbers you have heard are a common preference, but monks can and have effectively used anything from 'nothing' (341) to 'stratospheric' (4??) depending on the situation.
Well me personally i prefer to run with 550-560 but while im waiting on my choker and ring from coils (should have tonight) im running 553 skill speed or 572 skill speed or if really wanna go all out 491 skill speed and even with the 572 ss on dummy parse i can still reach my 2nd invigorate with using 3 fractures and constantly keeping tod up, in raid tho its even easier even more so with a ninja that 491 skill speed is very nice with a ninja and in turns like t13 while earthshakers are on me makes its very easy to keep gl 3 up.