The Quack Pack has become tame enough that I can pick them up individually without trauma, so I weighed them last night:

RatPhooey (who is still licking my hands) 9.2 ounces
RatHuey 11.2 ounces
RatDewey 14.6 ounces

Not going to mistake these guys for gerbils!

I never weighed my biggest rat, Ratatouille, but he had to be bigger than all three of these combined!

RatDewey is unusual because he very gently takes treats offered by hand -- RatHuey snaps at treats like they were the last ever in the world, even trying to yank on the spoon if I'm giving something like yogurt or cottage cheese -- RatPhooey is in-between, wasting no time getting his share (he often runs off immediately to stash it and come back for more) but not endangering my fingers in the process.