I think I mentioned a couple posts ago that I have the Hughes shims that I never used when I put the rockers on my factory heads as they were exactly the same as my 273 rockers.
If you can use the shims to raise the shafts and get a picture without busting a saddle you can do that. The issue with the shim like that is they only raise the shaft and they don’t move the shaft away from the valve. Using those shims will at least let you see which way you need to go, and you have them.