We sync hand timers same as always -- about 45 min before the run to give people time to get onto the hill. Electronic timers are sync'd ~15 min before 1st run to the same base. So, as Matt said, they're close. I also re-sync hand timers before 2nd run.
By the way, USS&S has chosen to interpret the rule change as disallowing sync prior to 2nd run, but I've never found that in the rules. 611.2.1 says to sync as close as possible to start of 1st run and not to re-sync during a run. But nowhere does it say not to re-sync prior to 2nd run. I like the new interpretation. Since start and finish times come from the same timer, re-sync is unnecessary, but it certainly doesn't hurt anything.
For hand timing, since we're taking start and finish times from different timers, sync of the stopwatches is absolutely critical. However, they need not be sync'd to the electronic timers. It's convenient when comparing absolute TOD, but completely unnecessary for calculating run times.