Look, you can get a number of answers on this question nd it all depends on the engine power, weight of the plane, altitude you're flying at.

For the TT .46-pro you can use a number of props, but I'd say that the 11x5 is good for a trainer.
It's lower pitch compared to the 11x6 makes it a bit slower which is good for you.

Generally when you speak of props you say that the bigger diameter makes thrust and the higher pitch makes speed.
The first number is diameter 11x5 and the last number is pitch 11x5

E.g: Take the same plane and prop it diffrently. A longer prop with low pitch will have great acceleration and power to pull the plane vertical.
The same plane and engine with a shorter, high pitch prop will hae bad acceleration, no "pull power", but when it get's going, it'll be very fast.
A good comparison is the gears of a car. Low pitch = 1:st gear.... high pitch = 5:th gear


Whatever you chose in the 10-11-12 X 4-5-6 will fly the plane, don't loose any sleep over it....As long as you get the 11x5