im curently on my way to make a 2h cav samurai build, i plan to use katana
It has 95 reach, a bit smaller then other 1/2h weps, but when i played 1h cav, i often grabed morningstar and used it with shield, it has 13 less lenght then katana bit still it was very effective.
Considering katanas super fast speed, 30% penalty wouldnt be that much.
And im planing on having 8ps so even in damage side 30% penalty wouldnt be much