I use rapid synth personally the failure rate being no different then hasty hand in the condition I use it in so I am never worried about finishing the hq is more of an issue for me. Piece by Piece while is powerful and independant of everything except failure is nice but piece by piece is actually not more powerful then rapid even without ingenuity atm because piece by piece actually does less each time compared to rapid which is consistent but rapid not have a 100% is what makes piece by piece more diserable for 100% no rng as you will do it with steady hand up. Piece by piece true power is as i said independant of your stats just like flawless synthesis but with our stats at the range if you hit everytime rapid will always come out ahead. A gamblers chance which is why I don't recommend it to others even though i use it.