My adapters work pretty well to minimize the thrust forward. It might be a bit closer than most, but it works ok. When the DIN adapter is used, it's pushed farther forward and probably isn't going to be comfortable. I don't know for sure, since I don't have a DIN tank valve to try it on.
Thanks, JB. I have hella valves I could mod already.
The problem with your idea of screwing the adapter into the valve is that the regulator has to screw onto the adapter as well. Then, positioning the regulator correctly (like not sideways, upside down, or otherwise skewed weirdly) becomes a problem unless some kind of fitting that allows the regulator to be positioned properly is devised.
This is a similar problem that I have with my LP air tube on the Conshelf mod. One of the fittings has to rotate on the tube and seal with a ferrule or something in order to get an airtight seal with everything pointing in the right direction.
I think you should try, Phil, a different approach. How about making an adaptor for a K-valve that plugs into a stainless steel tube to and inverted set of twins. You can run the line from the manifold to the regulator above, like is done by the Siebe Gorman scuba unit in the 1960s:
Seibe Gorman twins001 by John Ratliff, on Flickr Hampton, T.A., Captain, AGR, REsc, AWLISA, The Master Diver and Underwater Sportsman, ARCO Publishing Company, Inc., New York, Copyright T.A. Hampton, 1970, page 16.
In this way, the depth of the regulator is negated.
I'm going to bring this back, as I really think it is an idea which could solve your problem. An inverted set of doubles, with a yolk setup on the manifold to a stainless (or copper) HP tone to the top of the tanks, with a valve mounted there (or just the hold mount) could be significantly behind the tanks, and therefore allow the Soviet regulator to be mounted further back. This would give you room to have the regulator in a more ideal position.
John C. Ratliff Diving since 1959, at age 13. Haven't stopped, and still enjoy getting wet.
Thanks, John, I see what you mean. I think the upside down tanks thing has loads of possibilities for lots of reasons, including the remote first stage/chest mounted second stage concept. This idea has legs, in my view. And I am planning to do some experiments with my AVM-3 second stage regulator in this configuration. But, I'm only going to live so long..... So many things to work on.
However, I don't think this regulator is jammed up into the back as badly as everyone thinks. It might be, and I haven't actually dived it. I tried to a while back, but the reg leaked through the ORPV at the pool, so I didn't get the chance. I think it will work fine, as is. It's on my list to work on (see above). And doubles ain't my thing...
I'm selling off as many of my normal regulators as I can, and I'm going to be left with my custom modded regs and Eastern Bloc stuff, so you might see a flurry of mods/repairs/experiments with these. I just ordered a bunch of Soviet parts from the Ukraine.