I read that method but decided to try a bit different method. I used a threaded rod, two nuts, and two fender washers. I put the rod in where the axle would go with the nuts holding the washers against the inside of the dropouts and just started turning the nuts to expand the rear triangle. It worked perfect. I remember reading somewhere that that could cause it to be uneven but I measured it all when I was done and it was the same on both sides.

I think I remember you from the C&V forum some years back. I had posted about the Panasonic there at the time and about the upgrades so you might have seen it. What I ended up doing was the new 700C wheelset with the 135mm spacing, a 9-speed Ultegra rear derailleur and 13x32 cassette, 9-speed downtube shifters, a sealed cartridge bottom bracket, and a wider, randonneur style handlebar. That allows me to run up to 38mm tires. The other thing I've been considering is crimping the chain stays. Obviously that gets into risky territory there and I wish I could find a frame builder who would be willing to do that. Lots of bikes have crimps in the chainstays for tire clearance but the Panasonic has just has round stays. With just a little bit more clearance I could run 42mm tires. And finally, if I really got a wild hair, I could swap the fork for a disc brake fork and have the bosses brazed on the rear for the disc mounts. The problem I've run into is that there are a couple of frame builders in this area but they don't like to do repair and modification work, they only want to build new frames.

EDIT: Forgot to mention, I changed the original half-step plus granny setup in front from 50/46/28 to a more modern 50/40/26. I kept the original Biopace outer ring just so that it looks like the original.

This is it here (I've since shortened the cables):