The "pro" is in quotes because I don't know what kind of professional I purport to be. Professional unpaid writer? Professional home hack mechanic? But if you use Tektro's road brake lever for v-brakes, I'm a proponent of this trick, which I'm giving you pro bono.
For whatever reason, the angle that the cable housing exits these levers is incredibly awkward on pretty much every bar I've ever installed them. Case in point:
See how the cable comes out pretty much perpendicular to the lever body, then has to make a sharp turn upward to follow the curve of the bar? It's subtle, but it's there -- and it's just enough of a kink to make the action of the cable rough. It works, but it just feels cheap and unpleasant.
The fix for this is really simple: Take a file to the lever body and remove a bit of the upper corner where the cable housing exits, allowing the cable to come off the lever at a more natural angle:
That little corner of the lever body serves no structural purpose that I can determine, and knocking it off lets the cable follow the bar in a smoother arc, resulting in a much better lever feel. Here's the modified lever all cabled up:
Very, very subtle to the eye (heck, I'm not even 100% sure I got my before and after pictures in the right spots), but a night-and-day difference in the hand, especially when I'm dealing with the long cable runs and resulting potential for increased friction on our tandem. Not bad for just a few swipes with a file.
(Disclaimer: I am not a professional engineer, this is not a manufacturer's recommended hack, my suspicion is that any warranties these levers might have are null and void after the application of a file, and you are taking responsibility for any chance -- however remote -- of lever failure that may result from this modification. Not valid in all states, selection varies by store, yadda yadda yadda trailing off into fine print...)