I bought one of these and consider it an extremely valuable tool to use on a lathe:
https://www.autismforums.com/media/center-height-level.14088/
The level itself can be calibrated to a box way on the machine so an exacting level on the machine isn't necessary after centering up the bubble.
The arbor provided for it can be chucked or held in a collet.
The spindle can be rotated to find the high and low points then turned 90 degrees to achieve a center.
From there, all that is necessary is dropping the index area of the level on the cutting tool front.
From there, using any kind of toolpost, the tool height can be set exactly on center.
I use an Aloris style quick system and have about 30 tool blocks, so most of my tungsten carbide insert type tools are in dedicated holders that are locked in place.
https://www.autismforums.com/media/cutting-tool-centering-device.11601/
My DROs have the capability of storing 250 individual tool settings, so using that system with it has it's advantages.
https://www.autismforums.com/media/centering-tool-and-spindle-mandrel.11600/
https://www.autismforums.com/media/decent-quality-adjustable-bubble-level.11599/
Edge Technology
Edge Technology tools are available on Ebay to boot
I do centre height the old way, with a dead centre and by eye. I get a good finish on aluminium but steel is rough. I think I may have the wrong tips but I'll sort it. My holders are a mixture of original Swiss Multifix type A along with some East German and German copies. Not sure how many holders I have but around 25. Here in the UK most lathes have a Dickson or copy of toolpost. Good by not anywhere near as rigid as Multifix which are toolroom grade. I have had a Dickson flex in use; it was done up tight.
Overall I prefer Multifix because you know just going by the numbers what it is. So for example a holder is stamped AD2075. A=type A. D=standard turning holder. 20=max tool height. 75=length of holder. Easy!
No DRO on my lathe. Yet to find one that doesn't block use of the cross slide feed stop (used almost constantly for repetition work) or obstruct other accessories that I might use.
Thanks for the link to Edge, some interesting things there.