Better Setting for a Gravel Bike Randonee event

Hi all,
we want use traccar on a Gravel Bike Randonee event
We're thinking which is the best setting to set on the Rider clients via QR code to retreive their position and to don't drain their smartphone battery.
Our needs is to know their position with a good precision so we're thinking to set client in medium mode and send data every 5 minutes
Anyone have experience or suggestion?

Another idea is to set Highest but I don't know if it will kill the phone battery

We're think to set QR Code with this extra data:

id=xxx&accuracy=medium&distance=1&interval=30&heartbeat=3000&wakelock=true&stop_detection=true

Thanks

How long is the event or riding timeline?

How fast can the rider drive?
-> "Our needs is to know their position with a good precision"
-> 5 minutes -> a long distance

We have a randonee with 300KM which start at saturday night till sunday late afternoon and we have 3 tracks on sunday.
We don't need to know the exact position of every rider but we want to have an idea of they are so, we think 5 minutes interval is a good precision and it doesn't kill the phone battery and also our server (we will have about 300/400 riders during sunday)