My comments are a bit late, so perhaps the OP has made his decision, but here goes.
My RGS has just had its oil pressure go low (20-W50 oil, oil pressure gauge fitted, 0 at tickover, 25 running and 45 when cold started) and I’m investigating. The figures used to be 20, 45, 70. Now the up and down play on the TS main is a repeatable 2.1 thou measured with a .00005” digital clock gauge. The motor was built up with 1.4 thou play. So I’m splitting the cases to get to the bottom of this.
Considering the OP’s problem, remember that once fitted, the pressure from the crankcase will shrink the bush, once fitted, by an amount close to the amount of interference of the bush in the crankcase. So it could have been made OK if his 0.00225” slack was measured unfitted. Fitting the bush will decrease the clearance in the right direction. I don’t know what interference fit he is going for on his bush, but if he needs to close it up by a further small amount, he could get it plated with e.g. electroless nickel, so that once fitted it will be squeezed more. If he puts on a thou measured as a diameter change, that will reduce the fitted bore size by about that much.
I reckon that a good fit to go for in these bushes is 1.2 to 1.4 thou. Car engine mains seem to be typically 0.7 to 1.5 thou in the manuals that I’ve looked at.
A good finish in the bush is essential, otherwise you’re just measuring high spots. Boring the bush, once fitted, with a very sharp cutter is a good start. I measure bores while cutting using Starrett wedge gauges as these are very compact and give a very repeatable measurement and you can use a digital external mike on them to get accurate figures. I am not a huge fan of honing as knowing that all the abrasive has been removed from a bush is a matter of belief. I think burnishing after milling might be a good solution. Or bore about .2 thou small and let the motor do the burnishing. HTH