David,
The Carf tank holds 44oz. which will be plenty. If you search turbine spark maiden you will find quite a bit of info on mine. Dave Wilshire built the first one and gave me some good suggestions. I made no structural changes to the airframe. The main difference is the wheels and brakes. I used Titanium main legs from Central Hobbies and Tams lightweight w/b combo which saved quite a bit of weight. mine is 10.5# dry W/P-60 and an additional 12oz tank. I am using 8mm of flapperon which required a little up trim. Speed brake does not affect pitch. If you set up flight mode for flapperon you can trim in the air for pitch. If you have any more questions post them and I'll share my experience. CG, Throws etc...I have about 40 flights on mine and she's dialed!

Todd