Yeah, this all depends on your weapon's delay and how much storeTP you have.
Sword strap is a -% weapon delay reduction, but it reduces your TP per hit as well. If it doesn't affect your X-hit build, it will be your best option. (Also the -weapon delay% from sword strap is calculated first, not at the same time as haste.)
If the StoreTP from Rose strap is needed for a lower X-hit build, then Rose strap would be the best grip to use in that case.
If, neither sword strap nor rose strap are applicable, go with Pole grip.