While you could fly an LT-40 on a TT 36, you'd spend a lot of time at higher throttle settings, and you wouldn't have much if any reserve power. It also limits the acrobatics and fun stuff you can do with an LT-40 later if you are that short on power. I'm not sure, but I'd expect the TT .36 to be about the same as an OS .40LA. But I haven't seen that engine in person, so I don't know if it's "hot" for it's size or what.

The LT-40 is a BIG plane for a .40 size trainer. With the .36, you'll be "on the wing", so you won't be able to do things like a sustained 45degree (or steaper) climb. You'll fly more scale-like. This isn't bad, just not the way many guys fly their models.

Given the choice, I'd go with the TT .46 over the .36. I have an Evolution .45 (that I bought used and abused from an ex-student who totalled his trainer after soloing and wanted to move to bigger planes anyway). I think I'm using an 11x5 APC prop, and I pulled the baffle from the muffler. The plane is also converted to a tail dragger, which is nice.