Don't do it! The TH .46 is a chancy machine -- sometimes they're good & sometimes they're terrible. The TT is a better engine in just about any way you can imagine. The TT will also match the TH for power if you put the TH muffler on the TT (power ratings are crap in any case). Additionally, with model engines you want torque, not peak power (unless you are building a speed model), & the better performers have longer strokes.

The rear needle valve set up is also a problem area for the TH. The major pressure drop in the fuel delivery system is across the needle valve, & the fuel will tend to vapourize downstream of the NV in the delivery line to the carb. Additionally, there is an a further pressure reduction across the throttle bore which will drop the pressure in the delivery line to the carb even more -- this promotes bubble formation in the delivery line & erratic operation.

I own both types & there really is no comparison -- stay with the TT.

One other thing that you will need sooner or later -- a garbage bag to bring home the pieces (I'm not joking).