We did the same thing on the other side of the car. This side took a little less longitudinal adjustment, but I also let the top move outwards by not quite 1/8”, to get a better line on the drip rail. Also note that I had to trim a little bit more off of this side to get that scallop to lay down nicely on the header.
All of these little adjustments are totally normal. Modern tops are actually quite uniformly made. (I think they use lasers or something.) All the seams are sewn by modern, space-aged craftspersons, at least as far as I know. MGBs, on the other hand were made by the coal-powered, usually-disgruntled, proto-humans of the previous century, as quickly as possible, and vary quite a bit from car to car. So, while the tops are quite uniform, the things they are going onto are most definitely not.