The .46 will do OK witht he 11X4, and that's not a bad prop for the Avistar. Better would be a 11X5 or 12X4. (my preference on the Avistar would be the 11X5)

Avistar is abit faster flying model than average for a trainer... For most .40 trainers I would advice the 12X4 on the .46, but the Avistar's higher airspeed and slightly less tendancy to float on landing approach makes the 11X5 a better choice.