ya know, if Ur gonna chop a tank and use the back end for a hump, Id look for a Suzuki tank to chop.
The back end of Suzuki tank is better for the hump part of the seat. The back end of honda Tanks usually have a very large "concave area" thats a pain in the ass to cover.
Also I find that the Suzuki Tanks are typically more narrow on in teh back and fit nicely with a stock uncovered OEM Honda seat pan..
I also have another chopped cb550K tank that Im gonna use on the stock cb550F seat. I found that the chopped back end of the tank is much wider that the stock unfoamed seat pan.