RE: glow 4 stroke versus gas
I concur with sticking with a good 2-stroke at first. Simple operation, lighter than 4-stroke, all the power you'll need for your trainer. Biggest plus of all is far, far cheaper than a good 4-stroke engine. For example, you can get an OS .65LA for around $130, where the OS FS-91 Surpass II goes for $320, the Saito .91 for $310, and the Magnum .91 for $200 and up.
Get a decent 2-stroke glow engine for now. Once you've been flying a bit and have advanced beyond your trainer you can invest in a good 4-stroke engine. Smaller, more affordable gas engines are becoming available as well, but are really still in their infancy. I'm keeping an eye on them myself, but for now I'm sticking to glow.