As someone has already stated, the Estes motors aren't THAT powerful. I've built a few 3 stage rockets in my rocketing days. They generally weigh MAYBE 100 grams when flight ready. That's an estimate, and probably a bit on the heavy side. No where NEAR the weight of a 40 size trainer. I usually used a fairly hefty "D" motor for the first stage and liftoff was usually relatively slow and graceful. The problem with putting thrust on the wingtips isn't one of wing strength (in this case), but one of aysemetrical thrust. You'll want all of your thrust to be along the centerline.

Also, the thrust from these motors only lasts a few short seconds, so dont expect to go blazing around the sky under rocket power.

Overall I'd love to see it done, but I think that just using one motor will be a bit underwhelming and basically "safe"

If you want to think big, the next step will be to put some stages in series to get a longer burn. Pick motors that have a longish delay to give you time to get yourself out of any trouble that you may have gotten yourself into, before the next motor kicks in.

Frank