DBBs and turrets is viable for a sci ship, because of the subsystem targeting. Multi-target DPS will be a little lower than if you went for single cannons and turrets, but you lose out on the subsystem targeting (I just accepted that and ran cannons, but it's a personal choice thing). Definitely don't go beam arrays, you lose out on a lot of damage and all your ability to achieve good positioning (you have to broadside for beam arrays, but have to face forward for most Sci abilities).

I would say you're probably overloaded on heals for STFing. Unless you're in a really good premade with all kinds of special tactics, when one of the big enemies decides someone on your team is going to die, they're going to die, every heal science can manage notwithstanding. Extend Shields might possibly help, but I'd be hesitant to give up A2SIF. Whichever way you go, I would definitely drop the PH for something offensive, maybe Energy Siphon (as much for the bonus to your power as for the enemy debuff) or TR (mainly because it locks down the heavy plasmas from its target).

But in all honesty, you're not going to get a Wells to perform as well as a Vesta in PvE. The Wells' advantage is that it can pull some nasty tricks every few minutes and is very agile. That's great for PvP, or so I hear, but for PvE the Vesta's straight constant damage output is far more important. Of course, if they ACTUALLY MADE SCI ABILITIES WORTH ANYTHING (ARE YOU LISTENING DEVS?) that wouldn't be the case, but as it is the Vesta dominates, even with people who use it as an MVAE instead of a sci ship.