Honostly, don't bother. I have them and they don't come supplied with the correct hinge pins:
http://www.rc-monster.com/forum/show...=&threadid=733
Today I had to hacksaw the "kick up" part off the rear bulkhead, so the normal hinge pins fit and I can fit my UE Widetrac arms.
Other bulkheads don't have a kickup on them and allow the use of ordinary hinge pins, the FLMs don't.