my first 742 case rebuild, need alittle advice please

Sorry if this has been asked before and I am sure it has but bearings are expensive and only want to do this once, I have a 742 case, it came with NO shims, gears sure grip etc, I have a new set of Richmond 323 gears and a used cone type sure grip, and new bearings, I have plenty of tools, press, etc, I have installed new side bearings on the sure grip and need to install the pinion and set the depth, the manual I have ( written by Larry Shepard ) is pretty helpful but it says to use your old shim pinion gear marking and your new marking using a chart to decide on shims, but I don't know what the old number was, so I read through some old threads hear and most say with a 742 case start with a .090 shim and go from there, is this correct?, any other tips? thanks