Which MII dropped spindles?
 

I have a STOCK Mustang II front end in my '49 panel and want to install dropped spindles while retaining all the stock Mustang hardware. I notice some retailers specify that their drop spindles won't work with the original rotors. Others whose spindles look identical (CPP for example), claim theirs will work with the original rotors. What's the difference? Which brand should I get to function with the stock parts?