I've come full circle on the whole tire deflation thing and have concluded that, as with so many things, simple is best.
When I was looking to upgrade from a stick I checked out all the options. Many of the more complicated/pricier models (i.e. ARB) required repeated removal of the valve cores. I didn't like the possible wear and dirt intrusion of this method (did I mention the high cost? :-)
Initially, I really liked the Staun idea, but again the high cost (I need 6 including my trailer) seemed unnecessary. I ended up buying some Chinese knockoffs and after redrilling the ports and calibrating them carefully I found they actually worked very well. The problem with this system though is that they are preset to a fixed pressure. I found that with varied trail conditions and tire temperatures they were rarely right for the conditions and I'd end up having to adjust anyway.
What I've ended up with are only slightly more complicated and expensive than my original stick. I call them my ”brass holes” :-)
They are Godeson tire deflators (there are other brands)and are only about 20 bucks for 4 ón Amazon. They are just a brass fitting with a big hole through the middle and a little tab to depress the valve stem. They let the air out VERY quickly. I simply walk around the vehicle attaching the 6 deflators (about 1 minute) and then walk around again to unscrew just enough to stop deflating. I then screw in one at a time, attach my pressure gauge and adjust to my final desired pressure. Easy peasy, infinitely adjustable, very fast .... and cheap.
This has become my absolute favorite tire deflation method.