Tom Hunt's "Vertigo" (looks and functions much like your Rig) was able to get good hovering pitch and roll control with thrust vectoring vanes behind his tilting, ducted prop, power source. With vanes directing the thrust of your turbine for pitch and roll control you would be able to loose three of your four attitude control rotors (and thier associated batteries) for big weight savings and forward flight drag reduction.

The short moment arm of the vanes did not provide very good hovering yaw control though, so you might want to keep your yaw rotor. But then again, don't you always want to hover into the wind especially if there is a strong wind? So, maybe the limited yaw control provided by the vanes is all that you will need. Of course, redesigning your attitude control systems is a pain, but if you can't get the weight down and/or improve glide performance by any other means, you might not have much of a choice. Anyway, I have the plans for the Vertigo if you need more info about vane setup. Good luck with your Rig II. I have really enjoyed watching your progress with the first one :thumbup: