I got nothing for title but read

[AskaRay]

You do know you wont be using feint only with a ogcd right like blunt blood or repelling the math is there if you can use it

I mean...
Feint costs more TP and does less damage than Heavy Shot, so if you want to run out of TP faster then go ahead and use it but honestly it shouldn't be in your main rotation or anything.
If you accidentally mess up and ABSOLUTELY NEED to double weave and you can't bother to hop out of WM to do that then go ahead and use Feint.