No real thoughts on the boomvang except to follow the manufacturers recomendations, and call them for advice if you have any questions. No one on here has close to the experience they do installing them.
As for the traveler... If you didn't buy a variable space traveler. Take the track you have back, and replace it with one. See Harken Small Boat High-Beam Slide Bolt Track - 1.2 m at Mauri Pro Sailing Store
they eliminate all the drilling, filling, cursing, and fighting to install new traveler track.