I've been test riding. As a result, I have made some minor modifications. 1) You will notice that the angle of the upper portion of the seat tube has been changed to better mount a rack or rear engine. 2) The brake levers have been rotated more to the rear of the bars. Just more comfortable for braking and keeping my hands out of the wheels. 3) I needed a flag so that cars and trucks will pay attention to me and not attempt to crowd me when they pass.
The trike seems to roll easily without apparent mechanical drag (brakes, wheels, etc.) The flag didn't provide significant drag either ... although any flag will provide some drag. The smaller hills that I've pedaled up could be easily spun up (spinning). I have a small gear on the front and a mega-tooth gear 42(?) on the rear. I'll try spinning up a steep hill tomorrow and see how it goes. I've stayed out of the smallest gears on the rear ... unless there is a tailwind or a good down-slope, it is just too stiff pedaling. Although it does go FAST!