using Myriad 3.5.1.7 and AutoTrack v 3.1.46

I have created a clock, some of the entries are required and some can be dropped, the clock selects various entries using rules, categories and styles, these can be of varying length, these I would like to be kept and not allow autotrack/myriad to drop the but instead drop other entries so as to size the clock time to the hour.