The trick is finding a machinist willing to invest the setup time.
No........actually "the trick is finding" the customer who would pay for the actual time required!
I have done many sleeve installations over the decades and I would say that for a number of reasons if one chose not to deck the block, no matter how careful an effort was put forth in the sleeve installation operation, even though it might only have required a minimum of a cut to clean-up, one is going to be relying on the gaskets' conformability sealing capability; but of coarse that is why it has been incorporated into the assembly in the first place............ Right?!
Generally, one should anticipate only say.........two to maybe three thousandths, but surely most often something less than five anyway (this usually only due to greater press value on installation and/or unseen damage in the "blow-up, when the cylinder wall collapsed pulling the deck downward about the sleeve area), cut from the overall deck surface in order to level everything up, that being attributed solely to the cause of a reasonable sleeve install. After that, what does the rest of the deck look like and why, as often when the surfacer (that of a proper machine type) makes a minimal pass of say a thou, it can at times be surprising what might be revealed of a deck that was thought to be clean and square?
Again, as is so often the case, it's just a matter of how critically one looks at something, as to how much they might actually realize.
Scott.
