How about this build? First, the FSD Interdictor, will allow you to do missions in enemy space for 15 PP points for each cargo ship you sack and destroy, which is a great way to build points. With the 32 cargo space, you can still perform limited cargo runs as well. The two SCBs will afford you longer periods out in space during combat, but you will have to emply the SCBs while your hardpoints are retracted, but the Cobra is so fast, that shouldn't be a problem to run, use the SCB, and return to combat. Of course, you should shut down one of the two SCBs so you are not using them at the same time since one SCB will almost replenish your full shields.
I also removed the 1D rail gun and swapped the 2 and 1 size beam to pulse lasers to free up power, but the 2D hammer is more than enough, and the rail and hammer will definitely overheat your ship when fired together. The 3 lasers will afford you with additional time for combat versus the rail by removing the ammo restrictions and otherwise limiting them to the hammer.
Honestly, with this level of an investment, I think you would be infinitely better off with a Courier, if you have PP rank with Arissa, or Empire Rank. Otherwise the DS. If you are interested for combat based missions, those two ships I believe are better than the Cobra, especially the courier, which will cost you 10 mil for a full A loadout and will have 500+shields to the Cobra's 150j shields.
Here are my builds for the Courier and DS if you want to check them out:
Courier:
http://coriolis.io/outfit/imperial_...2t6b5454f1.AwRj4zKA.AwiMIyNGSA==?bn=IC PP v01
DBS:
http://coriolis.io/outfit/diamondba...m07040440582t6b.AwRj4yKA.IwBhrSq5iA==?bn=DS 1
Both served me well, and they have very low repair costs for interdicting ships in PP.