I can give you three good reasons NOT to use the 46AX
1). The LT has a flat bottom airfoil and will balloon as you increase the throttle.
2). You will be more likely to get into a situation that will over stress the airframe.
3). The AX is an AAC engine and reaches its optimum running conditions at a given temperature. You won't reach that temperature because you LT will be able to fly level at idle. The engine will run cool and that's hard on this type of engine.

Come to think of it reason number 4). You won't be able to get the thing down to land w/o cutting the motor.

The LT is really a floater. A .25 is ample power for it. Either buy a bigger plane to go with the .46 or get a smaller motor.