Anchorage is 6 hours behind Montevideo
Best overlap: 2:00 PM to 6:00 PM in Montevideo is 8:00 AM to 12:00 PM in Anchorage.
Your shared working hours run 2:00 PM to 6:00 PM in Montevideo (8:00 AM to 12:00 PM in Anchorage). You've got a decent 4-hour window. Set a recurring time near 2:00 PM in Montevideo (8:00 AM in Anchorage) and stick to it. Just remember Anchorage changes its clocks for daylight saving and Montevideo doesn't, so confirm the overlap whenever the seasons turn.