The primary problem with rails is that their “effective” combat range is about the end of their “optimal” with long range ammunitions, unless your ship is bonused for either tracking (Megathron, Talos) or optimal (Rokh, Naga). The Praxis is neither, and among the battleships, I think the Praxis also has the poorest sensors, which means you need Signal Amplifiers or Sensor Boosters in order to be able to even target ships in the effective combat distance.
Railgun damage application is so poor that in fact you will need to rely on ewar even when you have a railgun bonused ship. Here’s a lengthy explanation of your options to improve application, with some charts:
Since you’re into drones, I’d recommend you to look into the Gallente line, unless you want to snipe hard, in which case it’s Caldari as Caldari are range bonused