For bigger jobs we use the 1. 7/8" or 2.00" tubing in order to support longer lengths and more weight. Many time also we can not mount anything to the ceiling and everything must be supported from floor stands, meaning that we have to fly-in the light from outside camera view. For the Urban Meyer Spotlights series on ESPN's College Game Day we build a studio in the rec room of the coach house and left it there for several weeks.
Most of the section of grids that I have are 5' long. I always keep ten sections in my van, for the larger jobs I keep the rest of my supply in a double snowboard bag available at an ski shop. They are relatively inexpensive, strong built and I can store 20/ 5' sections including connectors and crossovers.
For longer runs I also have several 10' sections.
See "GRIDS 3" on the Tips & Tricks section for additional uses of structural aluminum in productions.