I would advise to always coldset to 128-130mm when using 130 mm OLD hubs and adjust the dropouts so they are 100% parallel at this distance. The reason for this is in my opinion not the ease of wheel changes (because as said, you can put a 130mm wheel in 126 frame without much problems) but the fact that with the wheel in the frame, your dropouts should be 100% parallel to eachother. If you don't align the dropouts properly, this will cause unnecesarry stress on the bearings, which will cause play after some time. At least, that's my experience with neo retro builds. Correct me if I'm wrong, I would be happy to learn.
I would advise to always coldset to 128-130mm when using 130 mm OLD hubs and adjust the dropouts so they are 100% parallel at this distance. The reason for this is in my opinion not the ease of wheel changes (because as said, you can put a 130mm wheel in 126 frame without much problems) but the fact that with the wheel in the frame, your dropouts should be 100% parallel to eachother. If you don't align the dropouts properly, this will cause unnecesarry stress on the bearings, which will cause play after some time. At least, that's my experience with neo retro builds. Correct me if I'm wrong, I would be happy to learn.