You can't get more thorough than THAT!
So true Mike.The new replicas available these days are too thick and press too hard against the doors when shut
I replaced the door seals on my 504 cab with similar ones from a rubber store [clark rubber] and they were ok after the doors were shut with a bit of force. The doors looked ok and didnt stick out when shut. Then i saw on Der Franzose they had original rubbers for 504 cc ,so i ordered some. when i fitted them the result was the same. Still the same force needed to shut the doors.After a few years the force needed is still the same.I wonder about that - maybe there's a maker in Australia? Could be expensive though, without a large production run.
This seal of the 404C is a rather odd moulding with a double open U-channel and a single lip for the door seal rather than a loop. This is the problem with the newer seals too, as you point out: the rear of the door sticks out too far and the door handle button is brutally difficult to depress in some cases....and then if the clip strips are like these, you'd need to find a supplier for them too.
I got door seals from Comptoir de la Carrosserie and they were WAY to high for the doors of the 404C. I would not think the trunk (boot) seal would go any better from them, unless someone else with a 504C can confirm success with it.The one rubber i havnt been able to obtain is the boot [trunk] seal. The lid sits too high with anything i have tried.
This rubber was new in 1975. It's better quality than the new stuff that's all moulded together and that newer stuff is so thick it prevents the doors from seating properly. The removable steel clip strips rust out over time. This is visible in post #525 if you're interested.I thought the new rubber would come with new clips already inserted.