One other thing.

Cable disc brakes are meant to work w/ linear pull brake levers [ like the ones you see on most linear pull brake euipped mountain or hybrid bikes ]. Only one company, Dia Compe, makes a road brake lever that is compatible with linear pull or cable actuated disc brakes.

Shimano STI levers are not meant to work with cantilevers, let alone cable actuated disc brakes.

Also don't know that there is a road style hydraulic brake lever.

That's why my Trek 520 came w/Shimano bar end shifters and the Dia Compe road levers that are linear pull brake compatible [ my bike came w/Avid linear pull brakes ].