I have fitted brake boosters to my Nomad, with cantilever brakes. From my experiments, I found that the cantilevers they suite best are the ones with the brake stubs external to lever arm, such as the Suntour SE or '93 Shimano. With these, they increase braking power considerably and in my experience prevent brake squeal. That's probably more than you want to know, but the ones I used are the Tectro ones that Thorn supply. Not all designs will clear a mudguard with ease, but these do. I found that one fitted to the rear had the most dramatic effect, as the stays of the Nomad are not stiff enough to resist the induced twisting force. Your EXP will be stiffer.
Cheers from England