My wing wasn't warped and I had a tough time with it, so adding warpage would make it impossible.
I don't know enough about these planes (real or model) to determine whether it is real or kit design issue, but the inner supports are taller than the outer in respect to the wing, requiring the outer tips to have to be pinched together. There was no way to to clamp like that and even tape would be tough as I see it, since the supports are very delicate and can misaligned very easily.
The only way I got my wing on was to bail on the styrene cement and reach for the CA. And again, it was only because of your warnings that I was so careful. If I went in blindly (as I usually do), most likely I would have snapped something.
Otherwise, the kit went together so easy (I swear most of it doesn't even need glue it fits so well) that I sort of expected the upper wing to just fall into place.