When the original big EU-1 came out, it was really asking a lot from the current .61 powerplants. So the thinner wing was considered to reduce the drag and perhaps the weight a bit. I think that was what Wayne was saying in his article. I don't know what the wing thickness percentage is on the EU-1A, although I did have one. Used it as my back-up to a Tiporare at the 1980 Nats.