i have the same boat as the pic you posted just in green. Im pretty sure the stringers are fiberglass. I just added a monster tower and have over 1300lbs and it throws a good wake. i definately had to re-prop it, but it was well worth it
I got an acme prop. im not exactly sure what pitch it is. i have all the info at home but unfortunately im back at college. talk to the guys at either acme or wakeside and they will know exactly what prop you need.
Just an FYI... if looking into Ski Rays (inboards not outboard editions) it may also be looking for a boat called a SKI Max. Made by Maxum, very very similar boat, rare but if you can find one they are great boats and just as worthy as the Ski Ray.