pinion depth, how close does it have to be

What did you do exactly to get the side load (I'm assuming that's what you mean by resistance) against the ring gear to get a good read on the pattern?
I too used a side bar. This was my second attempt. What I learned but forgot already is that you adjust a certain side last or you may lose your pattern like I did the 1st try. I will post if I can find it.