I was actually asking myself the same question right now lol. Im watching my colombian rainbow boa eat his first meal since I got him and he's really taking his time on it but I heard that boas, aswell as pythons, can eat meals almost 6times the wideness of its head so i wouldn't worry about it. Take the advise that you got earlier and dont touch him for a fiew days...
p.s someone corect me if im wrong about the wideness thing
I'm sure it's possible, but probably dangerous. :[
Keeping the same rule of thumb with the mouse being the same width as the largest point on the snake is a good idea.