There is no reason to go through the same building process if you are building a model. The only reason you would want to build a female mold is if you plan on making multiple iterations of the same thing. If you were going to build a female mold, you would first have to build the hull plug. The plug would be polished to a fine sheen. Then you would form the mold(s) around the hull. Again though, if you are just building one, build two hulls and stop there.

Getting the shape right will be tricky depending on how carried away you want to get with it. You can go about it several ways. You could possibly ask for technical drawings from Performance Catamarans (or maybe M&M) and use those to establish some dimensions. You could use some photographs from several angles, scale them, and come up with some plans there. You could take an actual boat and measure it using a coordinate system to establish the major key points and build from there.

As far as mocking up a hull, there are several different ways you can do that too. I recommend strip planking with balsa over formers. There's plenty of information about how to do this on the web. Also I've got some information on my website about mold making. We're making a one meter R/C boat and about to get ramped back up on the project again. Link HERE

Infusion is no secret process. It's is a process where the fiber and reinforcements are laid dry inside the mold. Then they are sealed inside a plastic bag. A high vacuum is pulled inside the bag (compressing the components) and then resin is "infused" into the vacuum area through several ports through the plastic bag. The resin then travels through the fibers and reinforcements and is allowed to cure while under vacuum.