Have you considered using the Simply Automated DKIT-05? Contains a UCS master timer and two plug-in relay modules that go in place of the timer in each transformer.
Timer keeps very accurate time, has astronomical feature calculated by zip code, backup battery, and will run up to 99 different timed events. Extra components can be added for advanced control of other lighting, appliances, or electrical circuits.
Costs more than a standard timer, but it gives the client many more control options when the control source is not within the transformer.