Richard,
I apologize I did not have the time to look for the drawings last night. You are correct about the gear ratios. I decided to split the difference and have a 95 degree retraction / rotation angle (1:1 ratio on the gears). I built in a little toe in when the gear is extended, and a little over rotation when retracted. That is one advantage I see with the sierra or robart method. I think Brian Taylor has retract plans on his corsair plans which could also be adapted. You could get an idea of how those work by looking at some pictures on some build threads. I am pretty sure I saw a picture of those that someone had built on rcscalebuilder.com. The Brian taylor method is similar to the 60 size robart rotating retracts. It uses a gear on the end of the strut shaft which mates with slots cut into the retract frame. Anyway, I will try to get those drawings this evening when I get home.
Jeff