I got the 2nd charge on my IB3800's last night and the capacity did go up as Danny said they would. The first charge they all took about 4100 to 4200mAh. On the second charge they all took over 4200+. I reran one pack last night with about a 2.5 hour rest for the pack and on the 2nd charge of night the capacity went up again to 4350mah.
I am thinking its a safe bet that these packs can be run twice a night.
YOU will definately want to turn down your peak detects from what your used ot on GP3300's. Try 0.03 to 0.02.
Ray