Engineering gives the best DPS gain. Synapse Springs - Spell - World of Warcraft give 480 Int, for 12 seconds out of every 60, for 96 Int on average.
You can insert these lines to a macro with any spell to use the gloves automatically without spamming errors:
(This macro can also work with trinkets. /use 13 for the top trinket slot, and 14 for the bottom slot)
In addition to all of the above, the Nitro Boosts activation is an excellent perk. Flexweave Underlay and Grounded Plasma Shield - Spell - World of Warcraft are further perks.
Your Engineering calculation assumes that you get the full benefit of the 12 second buff. This overstates its value a little.
As you know spell damage is calculated at the end of a spell cast. If you start casting a spell with one second left on the buff then that last second of buff has absolutely no impact on DPS. You're also unlike to activate the buff at exactly 60seconds each time. For example, if it takes you 1 second to activate the buff after it comes off cooldown and one second of the buff is wasted each time then the benefit of the springs is 86.6 Int (480*(11/61)) instead of 96 Int. How much this devalues the buff is debateable, and I'm not saying my 86.6 Int number is correct. In fact, I agree that Engineering is likely the best DPS profession for T11 other then Leatherworking. However, it should be pointed out that 96 Int is the absolute maximum benefit possible and unlikely to be achieved over the long term. Thought, I know some people will change professions either way, and I am considering it as well.
The other question I had, was have you confirmed that Instant cast spells are buffed by the Springs when using that macro? I assume this won't be a problem for Wrath, Starfire, or SS with a cast time, but I wouldn't be surprised if there
Instants had an issue.
Leatherworking: 130 Int to bracers in place of the usual 65 haste gives a DPS equivalent of around 100 Int.
I realize that this is a 4.0 guide, and what you said here is very likely to be true for the entirety of T11 content. That said, you may want to include a comment that Leatherworkings advantage is likely to decrease in higher tiers of content.
www.GrayMatterWoW.blogspot.com - My Moonkin related Blog.