"This is a new area for me. I have done a good bit of reading in regard to a decent curved one-handed adze,"
I use a guttering adze for this, and the one I got came from Country Workshops, which I think has closed down. They sold them unhandled at a great price. While these were two handers, I would say the heads were on the small size, very easily controlled. With two hands you rest the work on the ground, brace both elbows on your knee area. Even the first time you pick the tool up, you are relatively surgical. Far preferable to blazing away single handed in my view, and almost impossible to cut yourself.
All that said, I would wonder for the scope of work you intend whether a Krenov style scrub plane would not be faster and more controllable. One can crank one of those out in about 45 minutes if one has a bandsaw and a planer, or reasonable wood to start with. In this case it would involve making a hollowing plane with a double cambered sole, which is a little intimidating, but in this particular instance, one would just saw a longi curve; cut a bevel on the edges; blend with a spokeshave. All the complexity related to matching curves an mouth opening to the blade would be superfluous in this style of plane. You probably already have several scrub or agressive Jack blades you could use.
Of course part of the fun is playing with the big boy toys. So I looked up that list that used to be out there for Dunbar approved tools, and I found: This one that took me back to COuntry workshops:
The midsize one is the one I made. I think the heads were like about 79 bucks in my day. Ouch. To bend the handles, you need a wacking big piece of wood, or to be making two at a time. I laminated mine out of two pieces of wood, and it kinda ended up looking flattish.
and the following stand out: Hans Karlsson, Svante Djarv, Gransfors Bruks and Tim Manney. Everything but the TM appears to be out of stock. Perhaps this is a good thing as they are pricey and I am saved from an impulse purchase
"Probably closer to my beginner status is the newish Narex, which is cheap by comparison. Has anyone used one? "
You can't ever be a beginner again, you have too much tool savvy and general experience. Not to my taste that Manney one, looks like it might rotate a bit, with the weight where it is. Though bagging one out from a plane blade or something, might soften my prejudices on the mater. My own feeling on the mater is there is so little adze work in a chair that it is not a big deal whatever you use. Pros have them in their hands for only a few minutes. And in my efforts I have stopped shy of the line, so they seem a little unnecessary. My reason for the scrub.
Another option would be the Barr adze, which is patterned after a Dunbar tool, so it should be OK. Kinda plain vanilla to my eyes. But maybe the lack of cranked handle, et all is because the underlying geometry is right. I have a set of their chisels; their framing chisels; and their carver's drawknife, which I think is the best I have ever used (other than a fragile antique I own). I bought a lot all this stuff, maybe 20 years ago, and at that time it lacked edge holding relative to other O1 tools out there, but they were working on it, so by now they should have it down, as there is nothing really to it, and there is masses of info on places like blade forums.