Most of the stuff id bother adding would just be echo chamber.
I know there are some others on the board who have fit duotight over flare fittings with warm water, some tools and ALOT of patience.
I also came across a vid sometime ago that recommended 3/4 turn on the ball lock flare fittings for the duotight connectors. I’ve been sticking with that and haven’t had any issues yet.
Have also read that star San will break the connectors down if you soak and/or keep them saturated. I use mine for all type of transfers beer/gas/BLC/Star San, so I make sure to take the ball locks apart and rinse out with tap water after I’m done using them for whatever.
And..regarding the multiple regulator setup. I’ve posted this before, so possible you’ve seen it already but just in case you haven’t. Makes kegerator use easy for carbonating, serving (4) and the extra line is usually for transfers or quick force carbonating something.