wrote:
any advice? am looking at using the jet ski hull's bottom half.

You will very likely spend as much money and will certainly spend much
more time converting a jet ski hull than if you simply got good plans
and started from scratch. (http://www.clcboats.com has a great scull)
You will also be a lot happier with the performance of a boat designed
for sculling. So -- unless you just get joy from turning one thing into
another (Lots of people do.), throw the jet ski hull away and make a
proper scull.