Ok, ya, that was kind of a bad description of where I put things. If you look inside the plane, and forward into the fuse you can see where the fuel tank goes through the firewall and into the cowl section. I'll define the cowl as the fiberglass part included with the kit that is not part of the fuse. Therefore, if you put the battery and receiver in the forward part of the fuse, about 5 inches in front of the servo tray, behind the hole in the firewall for the gas tank, you should have a well balanced plane. With the 91, please do as said in the previous post and glass the wing halves together. I would also recommend glassing the mount where the wing bolts go into the fuse and anywhere on the firewall you can get at. Your also going to need a much larger fuel tank for a 91 so you will probably have a balance issue on takeoff. I put a 12oz in it because I like the extra air time and what I did was to balance the plane with the tank half full. Otherwise the plane will have almost no ability to taxie when the tank is full. It will nose over. I get 15 minutes at half throttle with that tank, but you will get about 10 with a 91. A very important step you won't be able to ignore is to trash all the control horns and clevasis (sp?) and but the higher quality dubro stuff. Replace everything you can and loctite or ca all the bolts and screws. Take your time with it and make sure everything is perfect. Its a great plane, but you have to go the extra mile to make it last.