Gave in to the prong
DDog has started to outdo me in physical strength and was getting to be an issue with stuff he wanted and I didn't, while treats, distance etc. did not work in the real world.
After studying the prong videos from Leerburg and others I finally decided to open up my mind and order one from Leerburg in combination with their prong collar leash that I attach to his regular nylon buckle collar as well (not their choke nylon collar).
The result: a better behaved dog, much better focus and no more rodeo-ing with him in life-pops-up-situations. I still use treats and clicker and must say that the combination of both, previously thought as incompatible, work very well.
He accepted it right away but I make sure that I am still training him as a 6 month old pup, which he is.