I don't think you need a fancy program.
The important thing is to do more total pull-ups/chins in the same amount of time, or the same amount of pull-ups/chins in less time. You can alternate this with working weighted chins/pull-ups - start light, and add a small amount of weight each workout (1lb would be good - it'll add up fast enough).
So if chins/pull-ups are a priority, something like:
Day A
10 minutes to do lots of pull-ups. It doesn't have to be as many as possible, just aim for the number generally increase (it doesn't have to increase every workout - everyone has off days). Don't do too many reps on the first sets, pace yourself.
Day B
Weighted chins/pull-ups, 5 sets of 3. Start light, gradually add weight.
Done 2-4 days a week.
Use whatever grip you like, or vary between chins and pull-ups. I'd recommend doing chin-ups for at least some of your weighted work though, if not the bodyweight stuff as well. If you stall, take it easy with chins for a couple workouts, then start again with the total reps or weight slightly reduced.