Just me, but I would never get shoes that are too small. If the heel is a bit wide for you (if the heel is slipping, it's generally because the heelcup has a bit too much volume for your foot, the solution is not to jam your toes up to the front. You should have a half finger, at least. of space between te end your toes and the very end of the toe box. if you have a bit of heel slippage, probably the best thing to do is either wear thicker socks, or use a heel insert.
Yeah, makes sense. Thinking back I have some Jack Purcell's that are pretty snug and they get uncomfortable after a while. Don't mind using inserts so I'll likely go 41.