When I mentioned monkey diving, just slinging one tank on the side(can't do that with heavy steels btw), its for single tank recreational diving. I really only do this when I don't want to pack two sets of gear, or if my recreational BC is spoken for...
For bigger tanks... Fabers... 85s and down, Worthingtons. Atleast IMO.
Bugman, what do you mean when you say "Heavy Steels"?
I picked up some HP100's because they weigh the same as the AL80s. Are you speaking of the weight, or the buoyancy characteristics?