G'day Matt,
Agree also with some other posts, buy a normal size swag (never know when u or a mate might need it).
Buy the best one u can, we've got 5 at home, all different brands, some bought 2nd hand, one from ebay, mine i got a hardware shop in Charters Towers and one is a burke n wills, which is a pretty good unit too.......
Another tip is to grab a set of those double bunk beds, leave the bed frames set up, even rivet then together, store them flat on or under ur matress in the ct. When u set up u only need to put the upright sections together, which will only take a minute.
The youg fella can sleep on the bottom bunk, the top bunk can be used for your clothes bags etc, gets them up off the floor, and makes sorting through them easier, no crouching down etc........