You may want to lower the tank a bit. The Sig Cub has a "tank floor" that is notch located behind the firewall. It's no big deal to lower it; mine is still high enough that I can slide my Rx battery pack under it. You want your tank centerline even with to about a 1/4 inch below the height of the carb spraybar. I have a 12 oz tank in mine. My Cub was my first inverted installation, and I put an on-board glow on it to forestall any problems, but once I got the carb adjusted , it's run fine without using the on-board system. I still use it for starting; you'll have to put some kind of remote plug anyway if you go inverted, the glow plug just isn't accessible. I set my system up as a manual, and can turn it on and off whenever I want from a Tx switch (mine is the MPI SuperGlo).