...if your reason for the respace is to go with the greater cog capacity of the 130 mm hub, I'd be careful pulling spacers. As you have surmised already, you can run into problems with interference between the chain/cog and your stay. We do this job for people at the co-op here, and it's relatively straightforward, but there is a learning curve if you want to do it yourself.

I set the frame in in a large bench vise (use soft jaws), clamped on the BB face flats, set up with a reference measurement string that goes from one dropout to the other up and around the head tube. You maintain centering by measuring with a vernier caliper the distance on each side from string to seat tube using the depth rod on it...if you just grab and spread they often spread unevenly, and an older frame that's seen use is often off anyway. Final step is to realign the drops parallel. Good luck....there are a lot of guys who will do this wrong for you.

Look at the Sheldon Brown link for a visual, but the 2X4 on the ground thing will drive you nuts, because it's hard to control.