Greetings Duhawk49: I am building one of these with a Brison 3.2 52cc for a friend. I mounted the ign. right in front of the windshield former in the fuel tank area. I built a box for it, and one for the ign. batt, on the opposite side. The boxes are permanently padded inside, and out, because the fuel tank is a close fit. The tank floor had to be modified somewhat. I too put a fairly large hole in the lower right corner of the firewall, gritting my teeth the whole time. I moved the firewall back 1" to help when it came time to balance, and re-enforced the @%##$ out of it, front and back. Wound up putting the rudder servo, back where the holes are in the side of the fuse for control linkage to exit. This worked out nice as there is a piece of ply that is supposed to be glued in there, just in front of the tail wheel, that made a nice hatch. It balances nicely so far, with out the rx batts. (2), or throttle servo in it. BTW this is a Dynaflite kit, and is not done yet. Always glad to help if I can. Garry