Wouldn't common sense dictate that you should probably test and understand your tolerance and response to the benzo before using it for this crucial application? Then you'll better understand how to proceed on this in terms of timing and quantity.
Ultimately, one of the main reasons the benzo is there is you are the type to worry that the benzo is there. Like many of us. Which means you'll probably also be panicking in relation to many other aspects of this experience. So yeah, consider testing it, a benzo should be advantageous at the end of the day, not a hindrance.