Hey all, I'm hoping for some input/guidance on Optivisor selection.

I don't currently use one, but I know I need one or more, but I'm not sure which magnification, focal length, options, I need to be considering.

I've got pretty good eyes, certainly not as good as they used to be, but I don't need glasses that I'm aware of. I used to have perfection vision, but an early life of constant computing, and the past couple years of burning my irises out staring at yellow billets has started taking a noticeable toll. I've started wearing cutting torch shades for the forge work, since the research I've done on didymium glasses, indicates these are really only suitable for sodium flare associated with glass work vs the IR issue of iron work, regardless of what some tool suppliers like to imply. The cutting torch filter shades seem to block UV and IR effectively, and even with shade 2 safety glasses I've noticed no more lingering burn in.

Anyway, what kind of ops do you guys use optivisors for? Up close fit and finish work seems obvious, but what about grinding also? What sort of magnification and focal length do you use? I grind sitting on a stool, with my feet on the slack tub and my knees on either side of the belt usually, so I was thinking 10-14" focal for grinding? Do you find you need the 4" or so focal for fine detail? Or can you stick with a farther focal length and maintain good posture while doing finish work at a bench?

Any of the light kits or the loupe accessories a must? How about the comfort kit?

Are the "real" Optivisors better than the off brand alternative they carry at USAKnifemaker and else where?

Thanks!