My suggestions.......
If your ordering from US Composits (good choice BTW), order 5 gallons of polyester resin.
Now I would suggest getting the General Purpose resin for the price if you think some might be getting wasted in the learning curve. Get the b440 resin if your confident. It wets out much better and has a good consistancy to it.
As for the mat, I suggest getting the 1.5oz. I prefer ordering the mat tape rolls. It is not sticky like the name tape implies, but in a roll. It comes in different widths. 6" width about 80 yards is really easy to work with and is the best buy per yard to weight.
If you feel you willl need more, then you know what to get and what works for you. Better than over ordering and getting alot of stuff you may not be using.
Hope this helps you out.
And fiberglassforums is a great place to learn techniques and tips. Be sure to check out ALL the stickies. There are some on what fabrics work best for framing and others on tips to properly get the mat laid down. LOTS of info.