Things might be different in Aries, but given that no one has responded and that I'll probably archive this thread for use in the future:
Here's a Hero guide that I found from Dexless, a GMS resource:
https://dexless.com/guides/hero-reference.34/#1or2hand
TL;DR: 1 hands will be faster in terms of attack speed, 2 hands will be stronger in terms of damage.
However, shields will have access to more starforce and better potential tiers, so most endgame heroes want to have a shield equipped over Princess No anyways.