Steve - Hope my late reply gets to you in time. The sleeve timing was changed from 146/132 in the first version to 138/124 in the second version. IFFF you want to tackle this, feel free, but it involves a sleeve drop, either by turning the underside of the top flange down to lower the sleeve, or making a mounting fixture to hold the crankcase, mounting it in your 4 jaw, indicating it and then turning the top of the block down. Unless you really want to play with machine tools, its easier to simply buy a new p/c set. As to the bypass channels, you can cut the eyebrow reliefs in both the piston and sleeve by eye, and come out just fine.
One thing I'd suggest is that if you grind or mill sleeves for any reason, deburr the edges (and plating) with great care. If you do enough of them, sooner or later you'll miss a burr and scar the piston. The trick is to insert the piston rod first, from the bottom of the sleeve, so its upside down on the first trial fit. If you goof and scar it, you have now created an oil control channel on the bottom of the skirt, not ruined the assembly by scratching the compression band.