Sounds like you have enough to keep you busy!😁 The reason the RCM trainer works is because of the wing deseign, it has a very thick high lift shape. On the twinstar, personally I would not go with retracts. The twins are heavier. The last thing you need is to have your plane hit a bump in the grass and then collapse or bend. I have seen some Twin stars fly at our field and they seem to be ok. What ever you go with, I am sure that you will have fun. Cheers! 😁