Pwm Servo Feedback

I'd like to request a modification to the Pwm servo feedback skill to be able manually insert the min and the max -or to be able to move them into position with arrows before someone pushes the button to calibrate min and max. The reason is you can manipulate and move your servos but mine are using a screw drive and you can't just push on it because it doesn't move. It needs to be moved with electrical power. Yes I know I'm out there where nobody is going but there is a reason for it, screws don't collapse when power is withdrawn and it is much safer and more powerful. Maybe you already have a way to do it but I couldn't find it.