Weighted Chin Ups Progression

Hey everyone,
I just restarted 531 and so far its been going great. During the press days, I like to do weighted chins as supplemental work. I tried using the 531 template for the chins but so far it does not seem to be working. For example, I know what my max is, but I can hardly do 65% of that for 5 reps. Does anyone know of a good program to increase weighted chin weight?

Thanks

just keep it simple, pick a set and a rep range (10x3 8x4 5x5 3x8) and stick with it for a few weeks then change to another set/rep range for the next few weeks, rinse and repeat. No need to get fancy until you hit a big wall or something