I have to agree Gav, id bump the spotteds to the size up, and the childreni to fuzzy rats. A big bulge dont hurt em, there built for it mate.

my darwin (fussy bugger wont go rats unless there coated with mouse blood) ate 5 mice one after another tonite, hes pretty bulgy but itll be gone in about 3 days.
but smaller foods are a pain, by the 3rd or fourth mouse its really hard for him to constrict because not only is a mouse small, but hes already got a bulge, thats another reason one large feed (if they take it) is better than smaller feeds more often imo.
I m sure they get a real digestive work out from constant small feeds, that they wouldnt in the wild. I dont know if thats in any way negative but larger prey sure is easier!