Twin Propeller pitch question

I have recently purchased a 1989 Scarab 29' center console; for offshore fishing. It orginally had twin 150 hp outboard motors (I am told it was a bit under powered with those engines). The boat is rated for up to 500hp. I am repowering it with twin 1997 merc 225 EFIs (that I already own) and would like some insite as to what pitch propellers to put on these engines. I have a friend with a similar hull/weight boat with a single OMC 225 on his boat and he runs a sst 19p prop with a wot of about 44mph. Should I use a higher pitch prop? The boat weighs about 3500lbs, is equipped with a 2 ft setback transom. Any help appreciated.

 

My brother-in-law owns Heritage Marine & Outdoors in Beaumont, Texas. He would be glad to help. Ask for Rick Rodgers 409-861-4118