D3-FNC is such a good support build, and makes most activities really easy!
The shield mod of my choosing is the Reactive Targeting one, since it has the wides shape and therefor, theoretically, the biggest protective area (It probably won't make a huge difference, but that's my recommendation).
I've chosen to run my build with the House as the primary with Destructive and Predatory - Both top tier PVE talents. Without having to "waste" a skill on a less than mediocre first aid you can still regenerate health when you get kills. I've paired it with the Flashbang Sticky since it's probably the best skill for PVE and for sure the best form of CC there is.
As for secondary choose whatever you want, you probably won't ever use it. In my case I just run with another House with Destructive and Hurried for when we're engaging bosses and what not - where Predatory is more or less redundant (I usually just forget to switch tho, lol)
The pistol is a pre-30 one with Coolheaded for 'farming' back the signature skill.
The talents are also pretty self explanatory: Combat Medic -> Heals your teammates and your shield, On The Move -> Always moving so you're bound to proc it and get tankier, Precision -> It's always nice with more crit chance and crit damage, One Is None -> Up close and shooting the NPCs in the head therefor extending the mag size which increases your DPS.
At 9k Stam and 121k SP (Skillpower rolls on the kneepads and backpack, as well as 2 of the gear mods) the shield health is a whopping 2.350.001, which is the max, just think about that.. It simply won't go down (Giggity).