The senior Telemaster is a great flying plane. Ihave had mine since right after the article appeared in RC Modeler magazine and Hobbie Lobby started offering the kit over 40 years ago. What what I have read on these forums, the smaller Telemasters are not as forgiving. Ido not think you can go wrong with a Senior Telemaster

As far as which type of motor to select, it is mostly up to your personal preference. Electrics offer a lot as you do not run into issues getting them to start and no noise issues and no issue in obtaining fuel but you will need multiple batteries and ways to charge them safely at home and on the field. I also gather that flight time is less than it would be with typical glow fuel tanks. Battery technology has greatly improved.

I do not yet own any electrics but do want to start as they seem to have a lot to offer but some people prefer the smell of burnt glow fuel and the sound of a glow motor. In short, pick the type of motor that you like but be aware of the short comings of both types.