The 46-sized Katana is designed for a .40-.55 2-stroke which is quite a bit lighter than a .91 4-stroke so I would *not* recommend such a match if it's serious 3D you want.

You'd be much better off with the 70-sized Katana. We've got one in our club with a Magnum 91FS on it and it flies very nicely.

A .46-sized Katana with a .91 4-stroke would be a noise-heavy brick. Sure, it would fly but you'd never get the CG far enough back for really good 3D without major modifications (such as mounting the battery outside the wing, towards the tail).