Well, I don't know what you expected, but this is really about cooking an egg.
Some time ago I read about Werner Gruber, University of Vienna, who had found a formula to create the perfect soft-boiled egg. (More on his homepage, albeit in German.)
We actually do apply the formula at home with good success, but I had an urge to perfect it. That urge was triggered not by a desire for eggs (I hate boiled eggs), but by the annoying ignorance of people:
Twice already (in Zuoz and Flims), our hotel's breakfast buffet featured one of these egg cookers where water is boiling merrily while the guest lowers an egg into it. Usually, an hourglass is provided - together with the note that due to the high elevation (and water boiling at lower temperatures), one is to expect an egg cooking time prolonged by 2 minutes.
Which is nonsense, of course. Yes, if the water doesn't get as hot as in the lowlands, the eggs will need a little more time. But 2 minutes? I guess those "2 minutes" were introduced mainly to amaze the guests about the wonders of the incredible high altitudes in Switzerland. (That said, Flims is on about 1080m, you can well leave the oxygen tanks at home…)
If you play around with the numbers below, you'll find that, under otherwise identical conditions, an egg boiled on 2000m needs about 20 seconds more than its counterpart on sea level, the difference between 500m and 1500m of elevation is a mere 11 seconds.
Will the world now be a better place? I don't think so, but I can but try.
The preset default values below usually make sense, so if you only change the diameter you'll still be ok, sort of.
What about weight?
Yes, I hear you. It's a lot easier to weigh an egg than defining its diameter. A guy called Charles D. H. Williams has taken care of the issue and published his own formula, based on weight of the egg.
Now I am not saying the formula is useless (a simplified version is on German Wikipedia, BTW), but for me it simply does not work. The cooking time (to 62° C) of a 46mm/66g egg is about 30s less in the weight formula than in the diameter formula - but even using the latter, the egg is very soft.
So while I toyed with implementing the formula here, I cannot do so in good conscience.