When they say to strip away the covering, all you need to do is just cut through the covering, this should not take any pressure. You might make a small cut in the balsa, but as long are you are using a SHARP blade, it is very little to worry about. Just don't push the blade all the way through the balasa. Also, you can reinforce the "cut"with some thin CA . As for keeping the trainer as a back-up, if you have the stroage space, that's what I would do. I guess I'm lucky that I am currently plane "rich", plus I have storage space.