I had this exact issue, with the same radio. My Alpha 40 RTF came with this radio, and then I built a Four Star 40, and bought an identical radio for it. I set up all of the servos in the Four Star to match the Alpha, so I could use either TX for either plane.

Then I put together a Slow Stick using a GWS receiver on the same channel. That's when I learned the throttle servos in the glow planes were backwards, but on an electric, you can't reverse the throttle. I had to dedicate on of my TX's to the Slow Stick, and one to the glow planes.

When I built my Bel Air 40, I broke down and bought the JR Sport SX600 for $50 more. This low end computer radio lets you store 10 models with all of their trims, reversing, flaperons, expo, etc., so I am back to having one box that will fly all of my planes.

My first couple of times switching between the trainer and Four Star, I forgot to switch models, which was no biggie, except for some minor trim issues, but it would be catastrophic for the Bel Air, which has dual wing servos. I have now gotten into the habit of checking the model each time I start a plane, so I think I'm good.

This radio is probably the cheapest way to go. It provides basic functionality for getting 10 planes programmed and flying. It does not have some features, such as channel mixing or a flight timer, but considering it was only about $50 more than a flight pack with no TX, I think it was a pretty good buy.

Good luck