Perhaps and just maybe perhaps the new piece is a little small, you will need to reinforce it so you will loose a little room in the inside...
By this do you mean that I should give my hand some more room to move around in the glove?
I'm likely going to cast this and if I do, the internal folds aren't going to be there. It's snug now, but not uncomfortable and with the paper supports gone after a cast it will be looser. Does that sound right?