7.25 axel new pinion bearings set up

Okay, this project is kicking my butt! In hindsight I should have tried to take some kind of measurement on the depth of the pinion in relation to the case so I would have had a starting point. Even though I used the same brand bearings (Timken) and the same exact part number, they are not the same. To the last question above, yes the races are fully seated in the case. Just for recap, this is a '66 Barracuda with 293 gears in a 7-1/4 differential.
My new set of questions: Does anyone have a way to set the initial pinion depth on this when you don't have the setup tools referred to in the manual? I need to have that starting point in order to get this thing focused in. Currently I have .098 depth shim - original was .090 and I have added .008 in order to get the backlash within specs - currently my minimum is .0055 and the largest one is .008 so that appears to be good to me, but the pattern keeps coming out as needing to move the ring out from the pinion but when I do, backlash goes out to lunch. Any help you can provide is welcomed. I'd say I'm pulling my hair out over this but I don't have any to pull out.