I've made two sets of razor scales. No expert at all. The second set I glued the end of the razor with the spacer between the scales. I didn't want a pin there. I had not shaped anything. After the glue dried I put the razor in the handle (screw and pin) and when I closed it the blade was off enough for the toe of the edge to hit the scale. I was pushing on the side of the handle when the glue let go on one side of the spacer. This allowed the scales to move and then the blade was centered between them. I squeezed the scales together and clamped them. I drilled a hole in the end of the handle and used a pivot pin/screw to hold the end together. Then I shaped them and now the blade is centered perfectly.

Of course this is with a new handle and I don't know if it works all the time. I may have just been lucky this time. On my next set I plan not to attach the end of the handle until after I put the blade in and tighten the pivot. I like to use a screw/pin instead of permanent pins. Easier to adjust or remove the blade in the future. I have never used permanent pins.