Hi Michael,
I recommend installing everything as far forward as you can. My installation has everything but the ecu battery forward of the fuel tank. I didn't have to add any additional weight to hit the cg. I used the recommended cg from Skymaster and it seems to be correct. I did not install the smoke tank. I have been flying for 6 minutes and I'm landing with 1/2 tank of fuel. The K60-TP is every efficient. I did remove the main gear doors to prevent them from being ripped off when flying from a grass field. You will love the way this plane flies.
Kirk