Ah, now I see. No offense, I just hate working with the stuff. We sell quite a few buffalo burgers where I work (according to the P-mix something like a thousand in 2013) and I just don't like them at all. People seem to eat 'em up but the texture is off and they fall apart much more easily than beef burgers. Could be the supplier we use, and I'm not the guy pattying them up so I don't know how they're being handled. I don't care for the taste and they smell repulsive to me.
As far as beef goes I think 80/20 is fine but if the OP is finding that to be too dry, and if the meat isn't overcooked, then perhaps that ratio is to lean for that person. Or maybe it's been frozen, I dunno. Personally I think 70/30 is getting fatty to the point that you lose too much to shrinkage during cooking but depends on the situation I suppose.
As for the pan or plancha I think SpoiledBroth is spot on. I like to broil burgers but some of the best ones I've ever had were seared in a pan. When I make a burger at home I generally form the patty, vac seal it with a soft vac and sous vide it at 130 F for 2.5 hours, then finish it with 30 seconds per side in a screaming hot cast iron pan with a TBSP or so of coconut oil. It gets an amazing crust while leaving it on the MR side.