New deck on a Tracker

I *think* I'm going to build a new deck for the front of my Tracker, and I KNOW I'm gonna' build a dry storage box for the back.

What are the recommendations for sizes of aluminum I should use? I'm gonna' build the frame and the deck from AL, just not sure which size(s) to use.

Square tube for the box frame, or angle? And where is the best place to buy latches?

Thanks in advance, you guys are great!

J

BTW: I've got a guy who owns a TiG who owes me a favor, so getting this welded shouldn't be a problem. I might have some questions on that later though. Thanks again!