Surely the shorter one will be fine, especially as it’s an inner joint boot it doesn’t need to be as flexible as an outer, just make sure it’s on nice and tight and has the correct amount of grease in it, then just check it doesn’t catch internally when moved but looking at the both of them you have more space at the joint than the original.

At the end of the day it’s only a cover to keep the grease in and the dirt out. Unless this is for a concourse Car then just get one made.