Yes, you probably need less forma, but I actually made this so I could see if using [Maim] and [Pathogen Rounds] would be better than [Razor Shot] and [Augur Pact], and it actually was.
Basically what I did was trying to get similar cut damage and viral damage, and doing what I said keeps a similar damage proportion for the damages I care about for this build and increases the damage, so it's 100% better
About an actual guide for this build... Uh... Well, hold click, aim for the head with rank 5 arcane pistoleer and weapon go brrrrrrr I guess