Montevideo is 5 hours behind Madrid
Best overlap: 1:00 PM to 6:00 PM in Madrid is 8:00 AM to 1:00 PM in Montevideo.
Book within 1:00 PM to 6:00 PM Madrid time (8:00 AM to 1:00 PM in Montevideo) and both teams will be at work. A 5-hour overlap gives you a workable daily window; aim for earlier in it to avoid clipping the end of someone's day. Daylight saving complicates things slightly: Madrid observes it, Montevideo doesn't, so the difference flexes by an hour part of the year.