There is no magic velocity at which a gas check is needed. It's a combination of bullet hardness, throat and barrel dimensions, rifling twist and the pressure of the load that determines when a gas check is needed to prevent leading. The advantage of a gas check is you can have everything less than perfect and not suffer from leading.
Any of those bullets would be a fine choice, I'd probably lean towards the 260 gr as the availability in different diameters will allow you to choose one that fits your gun best.
