I currently have both the 4 star pulsar(elemental) as well as the 4 star prisma driver.
I have heard that the alchemer charge attack can OH KO gunpuppies (at 5 star).
If so, in how large a party would this be and would this be favourable over a.polaris in a party to have this?
(I am not a gunner so this is more of a utility weapon and I dont solo much)
Which would be better to upgrade?
You can one hit charge puppies if solo, and duo might be possible if you get ricochets from the other side.
Polaris > Alchemers on turrets, simply because you don't have to aim and it interrupts. It will interrupt turret in the action of shooting.
Edit: I didn't see you say you don't solo much. As long as you use the polaris on turrets, you won't bother your party.