I know you asked a simple question that may have a cookbook, caresheet answer, but perhaps you should take this opportunity to try and get away from the cookbook approach.
Just put them together and see what happens, then go from there. Or maybe try a larger cage and see if the pair likes to stay near one another, or mates on a few occasions rather than just once. They (the snakes) know when to mate and how and why better than any caresheet or even human breeder of hognoses does. Let the snakes tell you when rather than you telling them when.
It may turn out that the cookbook approach gets the required result generally, and that may be all that you want or need. In that case, ignore my post 
I don't know much about Western hognose in the wild. For example, does a male happen on a female in Spring, mate if she is willing, then they both go their separate ways? Or, does a pair court for awhile, or stay within a vicinity and mate on a few occasions until the female's instincts let her know the job is done? Are there usually multiple males involved?
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Mark
