You are right, the spine is not even and it is pretty obvious. The middle of the spine is narrower than the heel or the toe. I guess not using tape might flatten that out a bit, but with my experience I rather first learn how to set the bevel and hone from there than start correcting warps and other slight irregularities in the razor. Later, I might come back and do some correcting.

BTW. The hone bug really bit me as I am not liking my 6k king that much. I ordered a long and narrow coticule for this kind of problems and also the 3k/8k naniwa ss combo. That should get me covered.