Did the portable tank thing for a couple of months before I was able to move a small compressor up from the other house...Was a huge pain and took way to long every time.
Noid: Not going to be using a spring loaded reel...doubt they make one that big, but for enough $ they might...
We've got some spring loaded electrical reels at work. With about 60' of 12/3 industrial power cable on them, if they pop loose and get any speed going, it's dangerous. I've seen one cut loose and ****** a 100+ pound cart and it's contents about 25 feet and throw it around. Not a pretty sight when it's got a custom built maintenance computer flying across the hangar floor.