I'm pretty sure Dogmars are dialytes, so you can think of them as early Artars. Uncoated, with eight glass-air surfaces, I'd expect a fair bit of flare and ghosting. Small-ish image circle too. That said, they were not budget lenses, and dialytes in general can be very sharp.
The whole 'Berlin' thing looks confused but isn't really. Goerz were based in Berlin, and their lenses were marked "C.P. Goerz Berlin". They had a US subsidiary whose lenses were not marked 'Berlin' at all, but instead were labelled "C.P.Goerz Am.Opt.Co.". Then there were a bunch of lenses marked "Berlin Dagor" assembled by Burke and James in the USA from crates of lens elements carted off post WWII as war booty. These last ones are the ones that often turn out to be dogs. The first ones are, confusingly, often referred to as "Berlin Dagors".