For the Giant Big Stik, all I had to do to get the balance right was mount the battery about 6 inches behind the servos in the tail area. I used a balance point about midway between their original point indicated in the manual, and their updated point farther forward. The airplane feels good on the elevator and spins well, so I'm going to leave it where it is for now. Sorry I didn't weigh the Poulan before mounting it, but I feel the installation is probably as light if not lighter than their suggested Fuji engine as I didn't use the spacers and standoff ply firewall; I just mounted the Poulan to the glow engine motor mount and mounted that straight to the firewall.

Generally, if a glow engine drops in rpms when you take off the glow heat, it could use either more compression, or more nitro. One of my Kioritz engines is maxed out on the compression and runs fine with premium gas in the gas/glow mix. The Poulan drops a few rpms when you remove the glow heat, so it could probably use a touch more compression or a touch more nitro, but it would be difficult to raise the compression of the Poulan, and I don't want to run multiple mixes of fuel, so I'm going to leave it as it is. ("If it works don't fix it") Right?

Note: I have a smoke tank, pump, plumbing, etc., in the nose of the airplane, and the fuel tank on the c.g. Without the smoke setup, it would probably balance with the battery mounted with the receiver.

AV8TOR