It's an older thread but I think we're still on track. The fermentation temperature depends on what yeast you use. Champagne yeasts are pretty forgiving, but if you want to use an ale yeast for example you'll want to pay closer attention to the temp range, mainly to be sure not to have it too warm because that can result in off flavors.
Aging on or off the lees I think is personal preference. It seems aging on the lees imparts more flavor but it may not be a flavor everyone enjoys.
How much honey you use depends on a couple things. First do you want a dry mead, or are you hoping for some residual sweetness? For a dry mead you take the max abv your yeast will tolerate such as 14% or 18%, then estimating the sugar content of the honey you can use something like the gotmead calculator to determine how much honey you need in how much volume to get that (very roughly it's 5% abv per pound of sweetener per gallon).
For a sweet mead you need to use either so much sweetener the yeasts can't eat it all before reaching their max abv, or, you have to stabilize it later (i..e kill the yeasts off) and add honey 'backsweeten' to taste.