I usually use 1/8" wide scales, sometimes thinner. I tried 3/16, but it didn't feel right in my hand. If I use a spacer, the spacer is the same width as the spine. For wedges, I make the maximum thickness to be half the width of the spine and taper down over about 1/2"

To tell the age of a razor I usually just google the company name and model name or number on the razor. 80% of the time it leads me right back here to SRP where someone has identified it with a rough date. The other 20% of the time I usually find some kind of company history. To a certain degree you can guess from the original scales and monkey tang. You could also look them up in Goins. And obviously, you can post pictures here and ask the masses.

Honing and restoration are two separate processes in my opinion. While a lot of restorers hone, I could see sending it out to be honed to have a professional edge on it.

New razors are stamped from sheets of steel and come with a factory edge on them. A professional honing will set the bevel on it (the critical part) and deliver it back ready to shave. Once the bevel is properly set, a casual honer can maintain the edge with a 12k or 8k.

I hope that helps some. If not, feel free to expand your question.