In reply to EspenK:
I've always been able to do quite a lot (relatively speaking). But it doesn't correlate that well with climbing grade. Two other finger edge measures are more useful for measuring where I'm at compared to where I've been at in the past. How this might compare one individual with another I'm not so sure:
1. How fast does max two-handed fingertip pullup capability fall off if I do a set, rest for a minute, get back on and do another set, rest for another minute, get back on and do another set etc. I'm not sure if this is a good way to train power endurance, but I've always found it's a reasonable measure of my personal level. So, when unfit, I could usually do a good first set total, but the numbers attained thereafter would fall off dramatically.
2. On a given edge, what is the least assistance needed to hold body weight one handed? - a measure of max strength. This is a reliable guide to my personal bouldering ability, on problems requiring finger strength at any rate.