Speaking with decades of experience.... ABSOLUTLEY DO NOT USE A SERVO REVERSER. They are not very reliable and often the causes of crashes. Simply plug the servo into another rx channel and do a mix with the radio. If you don't know how, pick up the manual and read it. If you value your pricey build and want it to last a long time, do not use a servo reverser.

Didn't read all the posts, but if you used a reverser, it can cause twitching. If you didn't use a reverser, then you most likely have a bad servo ( servo with a bad potentiometer ) which causes other servos to twitch by giving unwanted feedback into your RX. Find it and replace it!