As it is getting more and more difficult to find his older works, and even more so in the same spot as the newer ones, here is an archive of the files. The inflation is put at the end (p93 to the end) to focus on otherwise hard to find vanilla fat stuff.
Order : 2-37 Colored Twitter art 38-66 Twitter sketches 67-92 Older art from the old website 93-end Inflation stuff (newer to older)
Active Twitter (last update as of day of posting 12/15/2021) : https://twitter.com/katohayabusa29
Website (no longer reachable unless using Wayback Machine) : http://katohayabusa.sakura.ne.jp/