Or much better for the model to be a fair bit lower? The actual height of the piloted aircraft is not known accurately. It depends on the altimeter setting used - and that is given by ATC.
PS I often use an unmanned airfield also used by model flyers, and have no problems. Overhead join to give them time to land. Don't do too many T&Gs so they get a chance to fly. Chat to them on the ground.