I just have one piece of advice. Unless you have shoulder mobility issues you'll be fine with a standard single piece harness.
Very true. The vast majority of 100's of thousands of BP&W in use today have no provisions for quick adjustment, quick release, "adjust on the fly" etc.
I have come to learn that much of the demand for buckles / QD's / slide 'O' matic harnesses stems from the way *jacket* BC function (or fail to function).
The typical jacket / vest BC attempts to control tank position with nothing but fabric. That leads to divers cinching their harnesses a snug as possible in a futile effort to keep their tank from flopping around.
These "jacket only" divers assume they will have to wear a "Hog" harness just as tight, and quite correctly anticipate difficulties getting into and out of a tight, eye popping hog harness.
What they don't realize is with a rigid plate there is no need for a "Marty Feldman" tight harness. The tank is secured to the plate, and the plate takes the roll out of the assembly. The harness, with shoulder straps, waist strap and crotch strap simply act to position the plate on the diver, *not* rigidly attach the tank to the diver.
This means a hog harness can and should be worn more loosely than the typical jacket BC. Not sloppy, but with enough give to allow donning and doffing.
For those with special requirements DSS offers the Glide Harness Adapter, but with a correctly adjusted harness most don't need one.
Tobin