I think it would depend on what you tolerance is to benzos. I find small doses of klonopin (1mg-2mg) does not reduces psychedelics much if at all. Definitely not visuals.
In short: benzo's soften a trip but do not really stop it. A fair dose can soften it enough to stop spiralling panic in it's tracks though, in some cases it can solve a problematic situation but I do not recommend it. But that is not the topic here, and we have the trip abortion thread for that.