8 3/4 rear end confusion

Hey guys, hope everyone is doing well. I’m in the process of tearing down the differential and I have already ordered new bearings and gears. I’m going to reuse the carrier and just have a machine shop hot tank all the components and rinse them. It’s already taken apart. I have a question when it comes to assembly. I know that the lower pinion bearing has a shim underneath and between the lower and upper pinion bearings, there is a spacer with more shims. I also know that those spacer stacks may need to be adjusted in order to get the perfect bearing fit/pinion depth in the new setup. Should I keep the older bearings and shave off some inner material so that they slip on the new pinion easily in order to be able to mock up the assembly(possibly multiple times) and find the right shim stacks on the new pinion? My issue with this is that there might be manufacturing differences between the old and new bearings to the point where once I find the perfect shim stacks with the old bearings and then have the new bearings pressed on, it’ll be off. Instead, should I shave off material from the new bearings so that they slip on easily and then I can determine shim stack. I don’t like the thought of doing that to new bearings but I’ve heard other recommend that. The last option would be to just continue to press on and take off the new bearings without removing material but I feel like that will do damage and weaken them. I’m just looking for opinions on which of the three options is best. Thank you all!