You only need gloss black if you're using the "high-shine" Alclads - so Chrome, Polished Aluminum, Airframe Aluminum, and Stainless Steel I think.
And yes, Tamiya X-1 works very well. When I was Alclading a wing recently, I used Tamiya X-1 + Tamiya Clear cut with Gunze Mr. Leveling Thinner as the base and it worked out very well:
If you're going with Duraluminum or something, you just need a smooth surface, but not gloss black necessarily. I've read of people having great results using Tamiya AS-12 as a base and think I'll try it on my next go-round.
On the Bench: 1/32 Trumpeter P-47 | 1/32 Hasegawa Bf 109G | 1/144 Eduard MiG-21MF x2
On Deck: 1/350 HMS Dreadnought
Blog/Completed Builds: doogsmodels.com