A big spare air or a DIY snuba (surface based tank, long hose and a harness to keep the reg pulling out of your mouth) setup seems most practical. If you don't want to deal with tank maintenance, just rent one. If you do it often enough for rental to be a hassle, owning a tank would be worthwhile.
Assuming you are doing this on your own, and not as a company with employees. That is a whole different can of worms.
Assuming you are doing this on your own, and not as a company with employees. That is a whole different can of worms.
