I just test flew this idea Monday after hearing about it for over a year. So far, it seems to work pretty good. the annoying thing with it is that you need to use both catylists.
First, measure out about 60% resin, and 40% bondo and get a rough idea how much catylist you would need for each seperately. Then mix the resin and filler till creamy, then add your drops of resin catylist, and your ribbon of filler catylist, and mix like crazy.
Good Luck!
-Sarge