Re: Has anyone used parts from this guy?
You don't necessarily need to do all cylinders, if only one needs it. If you do get machine work done, only take it to a marine OB machine shop, not an automotive one, and let them tell you what oversize to use and which brand/model piston(s). Machine the head only to flatten, the block rarely needs it and get a shop manual (OEM) if you're going to do the assembly work.
Dhadley on this board can recommend a shop (I think Marfab - he can tell you who to talk to).