The PT 40, 60, or the Sig LT 40 or Goldberg Eagle all make great trainers and builders. I personally built my first kit as a LT 40 and found it quite enjoyable, as it's laser cut. It's also a bit larger in size and span than your typical 40 size trainers, although it takes the same recommended engines. Just make sure you match the engine size to the airframe size. You mentioned a PT 60 with a 46. It would probably fly, but might be too slow and lumbering as it would probably be underpowered a bit. Hope this helps.