Just about any setup is now viable for DPM. Pistol and MA will outperform the other setups, with FA pistol likely taking the lead, if only by a small margin. I think I'd have had enough IP to get shields on if I hadn't maxed nano programming or put IP into first aid since I never use it. Nano pool doesn't need to be raised at all, tbh. The problem you'll most likely run into trying to swap between pistols and shields is the multi ranged req on pistols. My multi ranged isn't maxed, but I can't imagine you'll be able to raise it much more without causing IP issues for shields. 1hb perks work now, and pistol specials hit fine compared to other weapon setups, they miss a lot compared to a profession like a soldier who sits on 1k+ more AR than we do at any given time.