Double Battle Forge is usually going to be a waste. That's 16 mana in the early game, which is a large enough mana investment that you won't be able to attack early. For 12-16 Mana, the other guy could play a Gorgon Archer, Knight of Westlock, Iron Golem, Vampiress, or Forcefield, which is far better at defending him than your extra equipment is at attacking.
There are very few circumstances where you really need to play 2 equipment cards in a single round. If you're playing 1 equipment per round, you can get 3 equipments out by Round 4. (this is when aggressive builds generally start rolling damage dice) That's enough for a Lash of Hellfire, Gauntlets of Strength, and a Demonhide Armor at a total mana cost of 8+8+3+8 = 27, which leaves you just enough Mana for valuable cards like Battlefury or Nullify. (always play a nullify, or your gear will get dissolved right away)
The most effective solo equipment-centric Mages are Forcemaster and Warlord (FM because of galvitar and forcefield; Warlord because he can use helm of command to Battle Fury or Whirling Strike every single round)