I'd love to! However, he has been having an "adult mouse or similarly sized rat pup", and there are... many sizes of adult mouse (at least at my local stores there are). That's why I'd like to weigh him, so I can figure out which size I should buy.
Like Bogertophis said though, my main concern is his comfort and encouraging him to feel safe, so I don't want to have to drag him out. If I see my chance I'll take it, but if he hides for the next 5 days straight, I guess I'll just get a small adult mouse? I'll figure it out.
I'd still assume he'll be fairly stressed & feed him on the light side anyway (maybe a hopper?), so he's less likely to up-chuck it. Snakes in new surroundings may not feel so brave right off.
Rudeness is the weak man's imitation of strength. Eric Hoffer(1902 - 1983)
“The greatness of a nation and its moral progress can be judged by the way its animals are treated.” ~ Gandhi