I use numbers for digital silver prints but don't for enlarger prints. I find L values of 94 for highlight with slight detail, L value of 6 for shadow with detail.

on the enlarger

If I am printing a scene with lots of blank white in close to the edge, like a white blank sky, a good visueal measuring device for me is the point where I can see the easel blades defined from the white blank sky... the blades will show as paper white and be obvious in the print... the more defined you see the blades the more exposure you are putting on the paper.