Sounds roughly right Tom, although, when I was "Lopezing" I calculated the weight using the max I could hang for 12s when fully warmed-up. I basically used the protocol on the UKBwiki:
The workout:
Warm-up 10-15min
Progressive sets: 10-15min
Hang 10 sec with 40-50% of the total added weight. 3-4 min rest.
Hang 10 sec with 80% of the total added weight. 3-4 min rest.
Hang 10 sec with 90% of the total added weight. 3-4 min rest.
Main Workout: 10-20min
Hang 10 sec with max weight. 3-4 min rest.
Repeat 2-4 more times.
although, I usually did more than 3-4 max-hang - or did another full set on a different hold.
Lately though, I've been using Probes' 5x5x5 routine - seems to be a half-way house between max hangs and repeaters - 5x5s hangs with 5s rests with roughly the same weight as you use for the Lopez max hangs protocol (calculated diferently but the results is similar).