pierce

not sure I follow, nor do I see any such on the article, other than the picture showing the sidepull install on a vintage lugged roadie and how long the cable should be. on this frame, the rear brake and both derailleur cables route under the top tube, held in place with three sets of three brazeons...

if the cable is secured too close to the v-brake, then it doesn't have enough flex and the noodle-side of the vbrake will be constrained and not move freely.

if you meant a cable guide for a canti, sure, I have that, I took it off the bike (it fit on the middle of the seat clamp QR shaft) when i removed the factory cantis.... I'm trying to figure out if there's any way I can make the v-brakes work without switching back to cantis.