<VV> Master Cylinder Suggestions

[Western Canada CORSA]

Hey all,
 
I'm just about to venture into the "ugknown".  The front of my RS will be
getting 55-57chevy 2" drop spindles, it looks like from all the info I have
gathered that it's pretty much going to be a direct bolt in, with the
exception of the lower ball joint hole, which will have to be reamed out.
 
Anyway, they come set up for '80 Chev Malibu front discs.
 
To get the brakes set up right I want to put in a dual master, but am unsure
of what application's M/C I should use, any suggestions?  The stock FC drums
are staying on the rear.
 
Regards,
Joel