When discussing cars like the Ariel Atom, Jay Leno likes to say it's the little things like windshield wipers and windows, etc. that are difficult. I think he really means doors. Judging from the Europa, getting doors to fit and not leak is the hard part. Expect them to leak a little. When mine was new, I remember that you could actually see an air gap between the door and the seal.
As to why your seal seems too big... I can only guess that Ray got the closest thing to the original but because it was so long ago, they may not be as close as we might hope. To really fit it, you may have to readjust your door. IIRC, I got my seals from Ray many years ago. They looked just like the original to me but then, when I installed them, I was starting from scratch hanging the doors - not with doors already installed.
You might give Ray a call and tell him the problem you're having. He may know the problem and have a solution.