Haven't we been through this issue already?
I understand that you want to build your plane as perfect as it can be, but with a TT 46-pro you're a bit overpowered anyway and will unlikely go full trottle to gain maximum speed.
I'd say that the 11x5 is a good choice since it provides a tad more thrust which is more useful than pure top-speed in a trainer.

As a total beginner you'll never notice the diffrence from a 11x5 or 11x6, you'll be busy flying, not performance tuning.

...Concentrate on getting that plane ready and get flying.
Eventually you'll get your own opinion on the prop-sizes.