The 5-blade prop on the Skipjack was 15 feet in diameter, which equates to 2.5" diameter in 1/72nd scale.
I thought that with a brass bush bonded in, the plastic prop would work, I've been advised that this wont work, but I'd still be inclined to at least give it a try. Clearly polystyrene plastic won't be as tough as nylon plastic often used for plastic props, but provided you don't deck it against concrete pond liners it should last a while. Worst case scenario- it goes home and you buy a metal prop.
If you want a metal version, you have three choices- make one, purchase the conversion kit that Dave supplies which includes the prop, or buy a scimitar prop, which I understand the Skipjacks used later on in their career. AFAIK, noone other than Dave produces a correct 5-bladed prop in metal.