Good Evening,

Don't forget the Chromega drum. I've processed probably thousands of 4 x 5 sheets in mine; I do all the steps from pre-soak through hypo clear in the drum and have never had a problem with solution failing to reach the base side of the film. As Jonathan correctly notes, any anti-halation backing will disappear in a later step anyway, especially if the wash is done outside the drum. A bonus is that the Chromega never leaks.