Oh! Why didn't you say you wanted to stop after doing 30mph 
OK my first hand experiance........
Pinion brakes IMO do just fine on the street for stopping after a short run. Now going down a long hill they may fade slightly if you use them the whole way but, I usually downshift (automatic) and let the engine do its job. I rode with george to tellico and we drove from Crawfords to the trails several times and back wide open. No problems at all.
So yes, you will be fine for longer distances with pinion brakes.
Mine work better than what I had on my 60's
