Also consider your target final gravity when designing your must.
Three pounds of honey sounds like a lot of honey per gallon until you realize that in a 5 gallon batch of mead at three lbs a gallon there is 15 lbs of honey with an approximate SG of 1.11 and a PABV of 14.85%.
If you take just about any of the Active Dry yeast from Lallemand, Laffort, LeSaffre, Red Star, yadda yadda yadda. Most of them will ferment this to dryness. So the pounds per gallon does not really stand up to to practical meadmaking in my experience. That's why I preach using a target original gravity that considers the fermentation potential of your yeast.
If you set the desired starting gravity level to 1.120, and the target volume to 5 gallons you'll see that the amount of honey called for is about 16.5 lbs of honey. I've found that the actual pounds needed to get to that level can be up to 18 lbs of honey depending on the kind of honey you are using.
I mostly use the final gravity as my desired product destination, and then design the must so the yeast I use will ferment to ABV tolerance and end up in that range.
As an example here are some figures for final gravity levels of dry through sweet meads from Ken Schramm’s book on page 64:
Dry Meads: 0.990–1.006
Medium Meads: 1.006–1.015
Sweet Meads: 1.012–1.020
Dessert Meads: 1.020 +
I basically just pick a mead I want to make, pick the yeast, mix up the must to an appropriate starting gravity that will allow fermentation to dryness, or fermentation to ABV tolerance with some residual sugar left over for sweetness.
You can take a look at my yeast test to get an idea of which yeasts fermented to sweet, dry and semi-sweet levels as the starting and ending gravities are noted in the log.
Hope that helps,
Oskaar