There's an amigados script to automate this process here: http://eab.abime.net/showthread.php?t=48478
It means you don't have to go through this process manually for thousands of files. You can batch the whole lot in one pass.
It is nearly the same process described in your guide. This works a little differently though, there is one separate disk which contains WHDLoad and the kickstart images so they are not duplicated onto every HDF file.
Maybe this is helpful to you?