Grease Volume in Gearbox

When using oil, it's to be filled to the plug.  Which is about half a pint.  I don't know how or if semi fluid grease settles to a level after stopping when hot.

My 1930 maintenance manual, says half a pound of good quality grease. That is for a Sturmey Archer gearbox. I think the dolls head box is quite similar in physical size. I have refilled my Sturmey box, and it was just about full to the brim when I refitted the end cover.

At room temperature 00 grease is a liquid so perhaps filling the gearbox to the level stipulated by the manufacturer would suffice but should you use the bike below this temperature would the grease fling around enough to lubricate those tiny crevices in time before wear begins to cause damage?
You could of course put an extra glob of grease in, in an effort to compensate for error.
In the absence of verifiable knowledge in this field you may have to resort to that well known engineering practice of "suck it and see".

... and remember - it's most important to make sure there's enough lubricant to reach the upper (main) shaft.  Low lubricant level degrades quick gear changes as well as causing premature wear.