I'm with troj too. I used a LOC Iris set up for dual deploy on my first L1 attempt. I flew seven dual deploy flights on other rockets using E and F motors to get used to dual deploy before my L1 attempt. For the L1 attempt I used an H123 in the LOC Iris and the flight went well (about 1,200 feet) except my motor retention wasn't good enough. I ejected the motor case. I found it after searching for about an hour. On my second L1 attempt I stuffed an I211 in the rocket and sent it to 3,415 feet and certified. I am really glad that I used an I211 to certify instead of trying an H123 again. If you are gonna do it, then you might as well do it right and have a blast! It will be a flight you remember for a long time so make it one that you want to remember.
NAR# 92125 L1
Total Impulse for 2011: 1,729 N/s
Total Impulse for 2012: 1,689 N/s
Total Impulse for 2013: 795 N/s
A:6, B:5, C:19 D:15, E:4 F:0, G:0, H:1, I:0