Funnily enough Airflow Performance Inc. (API) (Don Rivera) is where I get my RSA fuel servos done. He should know. Forget the amateurs 
You need the proper rig for doing this, not on the engine. Send your servo to Don and ask him to do what you want. On a homebuilt like yours, he can do even more.
He has always delivered completely consistent results for me, over about 3 servos.
One was overhauled as a precaution following a suspected fuel system issue but was prob99 this.
One was overhauled after some debris got in and produced a very rich cut at idle.
One was overhauled for the exchange engine.
Ahah. Will ask Don then
