I appreciate your reporting the aforementioned sites, there's a collection of guidelines that aren't entirely new to me. for example batteries at 60% charge store better than batteries at full charge.
Nice to have all these guidelines and observations in a single place/site.
Regarding your D2H (and D2X, D2Hs, D2Xs), one good thing about cameras from that period is that they used a small lithium battery (CR2016 if I recall correctly), to maintain the clock circuitry running, while other (recent) models have a condenser which is kept charged by the main battery, and will keep the camera's clock running up to a month if you remove the main battery. Recent models have a greater risk of depleting the main battery. When the condenser runs out of power, you would get the usual warning "Clock has been reset", and you will have to re-enter y.m.d.hh.mm.ss (usually the date is reset to 0:00 of January 1 of the year camera was produced).
It's easy to miss the small lithium battery , some people have never noticed it, it's located in the same compartment as the main battery, and covered by a small sliding door. Lasts years.
Ciao from Massimo