I am in the planning stage of building a Bruce Tharpe Engineering Delta Vortex, http://www.btemodels.com/vortex.html. The fixed gear will be replaced with retracts which means the nose gear will retract into the compartment just aft of the engine bulkhead that was designed for the fuel tank. Using an engine test stand, I confirmed that my engine will run with the fuel tank placed aft of the nose wheel compartment. This location places the tank at or barely forward of the CG instead of the original eight to nine inches forward of the CG. Now my question. CG locations on most kits and ARFs are shown with all equipment installed but no fuel. If the fuel tank is now at the CG location and fuel weight will never affect CG, do I still use the CG location in the plans that assumes the tank is forward of the CG. The recommended tank size for this model is 14oz to 16oz.