46 will fly the plane well. Less overall weight and longer flight times. You will need to take a bit more time to build speed before the first turn and you will lose a bit in the vertical. Tuning is the same as any ducted fan. Remote needle will help a lot. If you don't have one, leave a bit rich on take-off. Make sure the rear servo mount is glued securely, I would reinforce. Seal the thrust tube as these tend to leak exhaust residue everywhere.

The VX seems to like the Thorjet fan. The Turbax will work well also. I like the Weston mini pipe on this engine.