Here's another time-saver thought for the Eyeball 1.0 method - who says you need anything but the bearing surfaces rounded smooth?
You could have for example a 12-sided bolt in-between the lugs themselves, as that area doesn't touch anything. It may look funny but there's no need to make it *perfectly* rounded on those non-bearing surfaces. The only bearing surfaces I can think of are of course the locking lugs themselves, the top-most unlocking lug that rides inside the mating notch on the bolt carrier, and the stem itself. All other surfaces aren't even touching anything and so don't need to be pretty.
You'll have to make them at least 1-2" longer on the back of the stem than the longest you'll need them so you'll have room to clamp in the collets. Just be sure to make them long enough for a PSL style build or perhaps a little longer, and you should be good for whatever caliber you can dream up
ETA the only cut that concerns me is the matching angled cut in the trunion. Still can't picture how that gets all done up pretty.