I found the Telemaster to be large and slow. I also found it to be a difficult build compared to the other kits available.

Scratch building a trainer doesn't make a lot of sense to me considering the chasing around you will have to do rounding up all the various parts and wood sizes. My estimate is that you will spend more money rounding up parts than just buying a good kit. Additionally a good kit from Sig or Great Planes will have good clear instructions as well as clear full size plans. My first trainer was a Telemaster 40 and the second one was a PT40. I liked the PT better because it was more responsive. Later I trained one of my sons on a Goldberg Eaglet 20 which was a good fast easy build and flies very well. We hand launched it, incidently.

I see lots of people learn with ARFs and do quite well. We had a 13 year old learn quickly and easily on an Avistar with the semi-symetrical wing.

The Spad trainers take a lot of abuse and keep on ticking. Don't use a balsa trainer unless you have a good instructor. It's just too much work to demolish so fast without help.