generally spreading from 126 to 130 is no problem. I have seen reports of brake bridges breaking loose, but that means they were ready to go. On one frame, I just put it on the carpeted floor and yanked on it. I have an alignment table now, so I would do it that way. I built frames back in the 120mm days, and it was pretty typical to bend the rear triangle into position. Can’t do that as readily on modern steels, but in the '70s and '80s most steels could readily be cold set
Someone must have spread the Centurion I have on the trainer, but I should check the alignment. I would worry about the dropout alignment as well as the hanger alignment.