Stupid qq but, do you have the rules? I don't think they're on the website but it's seomthing like only one page - the office shd have a copy (I have it at home but am currently out on the road, sorry)
Either way, as I recall the rules are pretty loose - of course, your reh counts in your max 20 hrs of reh, but my guess is that as long as you have given the actors that 2-hrs before call for dinner for a call that is 4 hrs or less, it works -
push come to shove, just have your actors vote on it - and that makes it good. And looks like the way most REAL Readers Theater I've done works - a pick-up reh the day of before a dinner break before presentation - just watch the length of day (tho, unless the show is horrifically long, you prob won't have an issue w going long)