I am actually currently riding the Cobra with a pair of Union Contact Pro`s and am finding them a great match. I do prefer a slightly softer binding though. I ride the Cobra on everything from groomers, to steeps, tight trees and large moguls on black terrain and find the Pro`s work extremely well.
Now, as for the Rome bindings which are still my favorite bindings overall , The 390/390 Boss actually is a good match. I personally feel that the Arsenals were overkill in the stiffness and made the board a bit too responsive and therefore touchy. For Leo who is more park oriented, definitely the 390/390 boss. For Dreampow in the deep Japan pow, I would lean toward the stiffer Targa with canting. The Arsenals have turned out to be a great match for the Summit and I am going to use them on the Raptor as well.
After much waffling, I ended up ordering Flux DMCC lights. I am a little nervous that they'll be a little too soft but from what I've been reading they are stiffer than the Contact Pro's/390's and you and Leo have liked both on the Cobra. So will see