Manual timing, or chip timing? If the latter, would you do both chip start & chip finish?
Here’s an example of a dual-slalom race, timed with 2 devices:
https://www.webscorer.com/race?raceid=368489
You can view the setup of this race on the app as follows:
Tap “Race with start list”
Tap “Download start list from Webscorer.com”
Tap “Search for results”
Tap RaceID field, key in 368489 and tap Enter
Each racer raced both A and B courses, the times were added together.
The app operator starts the two racers at the time as follows:
Start type = Individual
Start the race clocks on both the Start and Finish device
At the start device, switch to the “Fast-tap view”
Tap the two bib numbers starting next
Tap the “Same time” timer button when the racers are given the GO command