Personally, I decided to go with an APE copy from China, less than $30 as I recall, postage included, and impeccable quality. The key to manual adjustment is to roll back the oil seal O-ring on the threads so that it doesn't add to the friction of rotation. I would estimate that this is at least 90% of the net force required to turn the adjustment bolt. No exaggeration. Once you do this, you can finger-adjust the tension with great precision. I haven't put any real mileage on the bike since then, but the plan is to run it 50 miles or so, then readjust to a firm finger-tightness and no more. Maybe check it again after 500 miles or so, then every 3,000 miles or once a year thereafter.
Any thoughts on my proposed maintenance schedule would be most welcome.