Hi Kat,
As you have mentioned "distance is within 1km for each device" I would suggest using 1km, not 3. If distance is beyond 1km then choose the higher value.
Regards,
Syamantak Omer
Syamantak Omer | Community moderator | Staff TSE | CWNA | CCNA | RASZA | RICXI | Follow me at https://linkedin.com/in/syamantak-omer-5949b6124