Any Scare Bird / Cragar SS (small bolt pattern)

Hey Guys and Gals. I was set to buy the scare bird conversion for my 9" drums, and I happened to email them to see if the kit would work with my Cragar SS wheels. I received a simple reply of "NOPE".
Now because the back side of the wheel (hub flange) is flat all the way out to the rim, I am wondering why they wont fit. I think the "rim" part of the wheel will not interfere either. I am just curious if anybody is running this set up? I really wanna' do this.
If its not a possiblity then Ill have to get either Rally wheels, which do not fit my build, or spend a Grand on new wheels before I can even get disc brakes! Not Cool. It seems the onlt wheels that DO fit the conversion is rally wheels. Or some 17's or larger.

Im hoping someone has some input on this! I was thinking about maybe spacers because I have the room for the wheels to come outward a bit more too. But..............?