I didn't hit a paywall, myself. I don't have any accounts that would give me access, either. Though Medium will usually block after some number of articles in a month.
Join us at the Vintage Computer Forum. Technical assistance on tap for keeping older computers operational. Troubleshooting assistance, parts supplier recommendations, etc.
When I came in the door in instrumentation work, they'd moved to self-developing photo paper, so we got to use the former darkrooms as additional storage space. CRTs came into use on oscillographs, with the physical galvonometers being replaced by a CRT about half a centimeter tall and 200mm wide displaying dots that were recorded on the photographic paper. They were better at high frequencies, since they didn't have to deal with the physical mass of the galvonometer's rotor (the shaft, coil, and a very small mirror), but since there were a few beams in the CRT multiplexed between signal channels there were compromises in what you could record on one record with a CRT oscillograph, too. Typical galvo o-graphs recorded up to 48 channels on 30cm wide paper, CRTs up to 16 or 32 channels on 20cm paper.
Galvos took a lot of time to set up and calibrate. Adjustments to each one's amplifier, travel range and optical focus, then testing & calibration on each day of use.
This is a multifaceted question--there's a whole toolchain behind any choice of hobby CNC beside the machine itself.
I have a Microcarve A4 that I outfitted with some over-specced stepper motors from Keling, with a Gecko G4 controller, all driven by LinuxCNC. I'm happy with my setup, which I put together in 2011. Now, I'd consider getting a Tormach, which is good for prototype level work (we have a Makerspace in the area with one.)
Consider where you'll get your designs--if you want to do your own, you'll want software ranging from OpenSCAD to ZBrush. If you need to clean up or do minor mods there's software ranging from simple FOS software to the full design packages.
Most packaged machines now expect some specific driver software like Mach3 or LinuxCNC. You should probably plan to use what the machine's community uses the most first.
Doing a more roll-your-own machine like mine is certainly possible, but be careful about choosing what specifications are most important to you. Size and accuracy are usually inversely related.