It's legal to shoot into the OB at any angle, even straight on, but as others have said, I don't think you can stroke parallel with the rail without double hitting the CB as it's blocked/slowed by the rail.
However, there is a legal way to hit the shot so the CB goes along the rail - use Bob Jewett's "Two Times Fuller" method:
1. Aim the CB directly through the OB, then shift the aim halfway toward the line you want your CB to take (measured on a right angle line as shown).
2. Stroke the CB at the halfway target at medium speed with straight follow. It will go straight toward the pocket along the solid white line as shown.
pj
chgo
View attachment 604559