Well the original Atari vinyl isn't completely flat either, at least here is a close up of the original stuff on my SW cockpit:

Compared to the Happ-Suzo pica:

About the price of the pica: i ordered it directly at Suzo headquarters in Oud-Beijerland, not far from my hometown. They still had a "pick up" counter then which made it a lot easier and cheaper for me to get stuff there. I do remember that Suzo charged me a little OVER the same price in Euros as it is in dollars on the Happ site. Remember this stuff has to be shipped processed etc. but they don't charge for that separatly, I guess it's included in that price. So, 3 feet would around the 20 euro range. However the "pick up" counter has gone at Suzo so now I would also be charged with shipping this locally IF I can still order it. There could well be a minimum order quantity now too because of this. Alternative is to get it from the US but I am positive that Happ has crazy shipping prices there plus a minimum order amount.
So I'm still interested in Bruno's Morrocvinyl pics to compare. I think the Oracal stuff will be completely flat.
Remember that the parts that look 100% flat on Atari cabs are usually not vinyl but Formica like stuff.