Well in the case of servo , we need good high speed servo in order to get max from your FBL controller . FBL will make your servos work harder so first thing is to take care of servos.
Also confirm that you have choosen the right frequency for your cyclic servo , otherwise it can be responsible for making your servos hot.

Today I had a maiden, every thing was perfect, heli was not drifting, tail was perfect, but I noticed head wobbles with ff flights, , zyx version 4

Switch the gain down a bit .
Then test at lowest headspeed and also on max head speed.

And also lower the Tail rotor Rc dead band to 0 or 10 in advance configuration

fine dhruva i'll vary the main rotor gain along with tail rc dead band, the issue i think is due to  the blades unloaded in vortex state or (check it tmrow)

move ur cyclic gain to 30 directly ur wobble will go