8 minutes of rest for 5 sets of chins. Damn! You just added 40 minutes to a workout. Supersetting them might work. But you can also do a density block for one of the two days. Since your numbers are already good, you'll probably be able to get 50 in 10 minutes or so after a few weeks. 10 sets of 5 EMOM gets you there. If you have to drop to sets of 4 or 3, you can add another minute or two. 12 minutes for chins is way better than 40. Just don't burn yourself out too quickly by starting at, say, 8 reps. . . .