It sounds like you are doing ok with Duffy
My Rockys weightloss is mostly noticed on his backend,some weakness,vet says he's arthritic but I believe it's because of his HTism.
With my 3,it's really nervy at feedingtime,Vinnie slurps all of his food,I have to sit with Rocky until he finishes the teaspoon of food with his pill,usually no problem,after he finishes he gets the rest.
Chico might just sniff the food and walk away,only to return later to eat,it's a constant moving dishes around so Vinnie does not eat it all,pain in the butt,but they are worth it