I'm not Vicious but I'll tell what I do and also make another statement.
1. Since I work in a mini circuit it takes about 2 minutes before I hit the same exercise, so I get around a 2 minute rest and it seems to work for me.
Statement, it seems to me that if your target reps are that low why worry about clustering to begin with, just go with straight sets of 5, concentrate on the 1st set and get what you can on the next.