since there is a lot of talk on the rocket box here I'll put in my 2c ...
I never liked the diagonal cross brace on the rocket boxes. I'm sure they were designed to reinforce the box in case a tank drives over them but they interfere with the ability to put rocket boxes side by side.
You can carefully drill the end of the tack weld off and then pry the extra metal off the can. then get a file, grinder, etc and grind the sides nice and smooth where the rivets were.
Smoother sides = less abrasion if they are against your stuff. Also I paint mine white keeps them cooler (especially if they have ecosafe toilet inside) and if you ever have to toss them in the river on a pin its probably easier to spot something white in the water ...