I have a guy who wants to try a sarge easter. I verified his span on the ball he wants to convert and his middle span is good at 5". His ring was 5 1/16". This will be plugged. He is a lefty. My question is how do you determine the span for his new conventional ring figer and what forward/reverse and left/right do you use to get a good release? Is there a good rule of thumb to start with and then fine tune ? He has average flexibility in his fingers and thumb. Thumb is at 1/4 reverse and 1/4 left (under palm). Thanks for any info...I searched the last 30 days and didn't find layout help....Al