although for switching regs I am finding it tricky at first; when not in use I have my backup set on the lowest setting to prevent freeflow, which means I barely get any air when I switch to it at first. Then I would accidentally set it too high when in use, and during a switch it would violently freeflow if I forgot to adjust it back down before removing from my mouth.
"Barely get any air" is likely an exaggeration, right? 'somewhat more difficult to breathe' might be a more accurate description of how it should feel, and the reg should still deliver plenty of air with the adjustment knob turned all the way in. Although I'm not too familiar with hollis gear, I seriously doubt any manufacturer would design a regulator so that the adjustment knob would actually restrict the air flow to the point where you can't breathe. It's a pretty subjective feeling when you switch regulators, and it's easy to feel like you're not getting enough air. If you
really can't get air with the adjustment knob all the way in, it's definitely not adjusted correctly.
It sounds like the reg has a lot of venturi assist, which would explain the 'violently freelowing' when you take it out of your mouth. Any well tuned high performance 2nd stage will flow air if you remove it from your mouth and don't turn the mouthpiece down. Once it starts, if there's a lot of venturi assist, that will really get it going fast, and that sounds like what you're describing. You might try turning the venturi assist off (or to minimum) if there's a separate lever or knob for that. That should not increase the cracking effort at all but should at least slow down the free flows.
Most modern 2nd stages have a lot (too much IMO) venturi assist, because the manufacturers have determined that small 2nd stages (more linear flow, less internal volume, = more venturi assist) and lower WOB numbers on the testing machine (venturi certainly helps achieve that) help move regulators off the dive shop shelves.
I like adjustable 2nd stages but the adjustable ones I use do not have venturi assist adjustment, so it's helpful with keeping my secondary from flowing when I enter the water.