RE: J. Roberts Flight Control
There are a couple other options available to you, and you may already have the components in your R/C stuff. If you do not intend to compete, you could install an R/C receiver and servo in the model to work the throttle. Fly with your regular adjustable handle and use a neck strap for the transmitter. With a 2.4 GHz system you would not have to worry about interference. The advantage is that with the Robert's system you must have line tension for the throttle (or elevator) to work. Lines can go slack, especially when taxying.
In my competition C/L scale models I use my JR transmitter in direct servo control mode. One insulated line is for the signal and a bare line for the ground. I use a neck strap for the transmitter and can control throttle, retracts, flaps, and bomb drop with my left hand. I fly much more R/C than C/L and my left hand is doing what it does at the R/C field while my right hand works my 50 year old Darwin (adjustable) handle.
Then you could put operating flaps on your model too.
Chuck