@amilcarlucas I think, my large 24" build with KV230 motors at 6S is not really comparable to @Jai.GAY 's copter regarding the relevant frequencies, so my FFT parameters may not be helpful for him. But nevertheless, my strategy to find suitable parameters may help also here. It is documented beginning at How to methodically configure and tune any ArduCopter - #282 by Hacky
Reagarding earlier posts in this thread:
I would be careful with lowering the “ramp up” power parameter and I think this is not the right one to address desynch problems. From my experience I can tell, that too low ramp up power settings may result in limits at the upper end of the throttle range, so you may run into a situation, where you cannot use the full motor power anymore (like limiting the throttle to e.g. 70%).
There may be particular motors, which do not play well together with BLHeli_32 ESCs, but desynchs can also have other reasons (e.g. to large / too heave propellers (too much inertial mass)). You could try to lower the acceleration (by adjusting the “maximum acceleration” parameter) but you should test that on a bench first and you should use that parameter only, if you are 100% aware of what you are doing.