happy day 10!
I don't know how long about weight, what I can tell you is that Maui went from 13.7 to 9 pounds. Then she got regulated, diet change and came off insulin - her recent vet visit she now weighs 13.4 pounds.
So, as long as he's not losing, give him time and he'll get back to his healthy, ideal weight. (I figure 13.4 is Maui's) It looks good on her.
and happy, happy day 10!