Well, first off, if you're going for 18% and very dry, don't expect it to taste too great for at least the first year or two...
That said, if you're still going to aim that high, I'd suggest step-feeding it rather than dumping in all the honey up front, too high an initial SG is harmful to your yeast. If you want 18% according to the mead calculator, you need to start at 1.140 if you want 18% with a finishing gravity of 1.000, that's a hard start even for EC-1118. I'd start the SG around 1.125, let it ferment out, but before it starts settling, boost the SG back up to just higher than you think you want it (if you want it a little sweet but not too sweet, 1.010 might be a good point to aim for so I'd boost the SG to 1.020 at least the first time or two), and let it ferment out, every time it drops below your target 1.010 (or whatever you select), push it back up just a bit until it stays or until you think it's reached the alcohol level you want, then stabilize it and backsweeten to taste. If you want it dry dry dry, you'll have to step feed in smaller increments, like every time it goes below 1.000, boost it back up to 1.000 again. You don't have to pick your finishing gravity now, you can figure it out by taste in a small sample once the initial honey has fermented out completely, add small amounts of honey until you like the taste, then check the SG of that sample, then you have a target SG. It's never a bad idea to hold back a little of your honey for backsweetening either.
I usually find that 3.5 lb honey in a gallon of water is about right to get 1.125 for a starting gravity, which if it goes completely dry is just over 16%.
As for spices and fruit, orange zest will give much more flavour than the juice, and if you've ever tried the JAO recipe you know what one cinnamon stick and one orange per gallon is like so you'll have to decide whether you want the spices to be strong or subtle, I find half of a cinnamon stick and the zest from one orange are definitely identifiable as such in a gallon of mead if you don't want them to be beating you over the head with their flavours. Other thoughts, a few cracked allspice, a clove or two per gallon, half a nutmeg...
"The main ingredient needed is 'time' followed closely by 'patience'." - The Bishop 2013
"Good grief! If someone wanted to murder you, all they would have to do is ship you a 55 gallon barrel of honey and watch you document working yourself to death!" - Vance G
"When you consider that laziness and procrastination are the fundamentals of great mead, it is a miracle that the mazer cup happens." Medsen Fey, 2014