It all depends on what style framing you intend to do. A post and beam setup will require larger stock (3/16 x 1.25" or 1/4 x 1.5" angle) while a truss setup will be fine with 1"x.125" angle. You can also do an all wood setup that would require no support by using vertical panels as dividers. Also realise that anything over 3/8" plywood needs very little support, say every 18" or so. The downside is wood get's very heavy very fast and your performance will suffer while using more fuel to get to the fish...
On aluminum decking I try to stay around 14-16" for .100" sheet and 12" for thinner than that.
Personally if I was going for wood I would use fiberglass coated luann (5mm sheet) with a 10-12" span between supports. Of course it's much simpler to just use .80" aluminum sheet and 1" x .125" angle.
For cutting aluminum you can use anything you would cut wood with within reason. I've used my chop saw to trim angle down, you just need to cut really slow and spray some WD40 on the parts to keep the blade from gumming up. Sheet panels can be cut on a table saw or skill saw, again go slow and wear ear protection, it's loud.
My favorite is using a sawzall with a 12" 16-18 tooth blade. Remember this, you want at least 3-4 teeth in the cut to keep the blade from grabbing. So cutting sheet stock I lay the blade almost flat and just pull the saw through the cut. It makes the cut nice and straight while keeping the metal from getting all bent up.
The one tool I don't use is a jig saw. The cut speed is too fast so the blade gums up and they beat the metal up too much
Jamie
