I've done a tiny amount of fingerboarding, I'm old so strength gains come slowly if at all, and I'm a complete punter. However...
I tried an approach similar to the Anderson's (or beastmaker repeaters) last year, using unweighted hangs: 4-6 sets of 6 reps, 7 seconds on, varying the rest from 3 seconds to 7 seconds off. I started with 3 seconds rest but this just felt like I was about to break, so lengthened it a bit. Total duration was 60-90 seconds. This felt like anaerobic capacity training, I was failing due to powering out.
After 10 sessions over 5/6 weeks, my 60 seconds endurance (10-15 move boulder problems) got markedly better but my pulling strength on single hard moves was hardly changed at all.