I think it's 1 Teaspoon per gallon. But basically what you want to do is by the 1/3 sugar break (point where 1/3 of the sugars are fermented (1.100 to 1.066 would be the 1/3 break) is add that tsp in. When I'm lazy I do a 50/50 split. I add half a tsp per gallon at the pitch of yeast and the other half when I get close to the 1/3 break. There are lots of schedules you can do (fatbloke says you can put up to 80% right up front without losing any efficiency) but it keeps the yeast consistently fed to have a healthy ferment.
You should also aerate once or twice a day for the first few days.
You may make a good mead in a faster turnaround time than the ancient times, but unless your PH is perfect, your temps are perfect, your SNA is perfect, your recipe to yeast selection is perfect, your mead could use some age when you bottle it (it will only get better anyways so why not).
Edit: as a yeast suggestion for meads, I've been enjoying some good meads made from RedStar Pasteur Red.
If you are feeling impatient, you may want to look into Joe's Ancient Orange Mead, or at doing a hydromel (a lower alcohol mead that requires less age because of that).