I would forget about the Quattro, it's outdated and the plan set is not really great. There are some things in there you will be scratching your head about (at least I did) if you are on your first boat. Resale vale will be low compared to a Blade.
If I was to build today, even for family use, I would have done a Blade. Cost might be a little bit higher, but so will resale value. Have a look at http://www.bladecatamarans.com, and then get in touch with Phill Brander.

I dont know how good practice building a small plywood cat will be for a larger project. Unless you intend to do a plywood or strip planked project of course. If the design you think about is a composite project, you would be better off building some test panels to get used to the various building techniques and then following a well documented set of building instructions like Farriers.