Gixerkev, you are on the right track.
What matters is the relationship of the pistons (brake calipers) and the piston int he master cylinder.
The calipers here use 4 32mm pistons. Of course, its times two because theres a right and left caliper.
I would be pretty confident that if these two were matched up properly, it would not put any extra stress on the abs unit.
I could tell you how I did all kinds of sophisticated math formulas to do this, or I could say I copied what brembo recommended, and found a ducat master cylinder to complete it with.
On this caliper and master cylinder set up (stock) its not bad, at all. The stock brake pads are very mild. Ebc are ok, but Vesrah makes a far better pad for this caliper.
If you use something like this, you wont need a master cylinder. Sure, it would be nice, but you dont need it.