Garmin
I second the motion on Garmin Tech Support. Give them a call. I have had sevral questions on my 182, and they have always been very helpful. As for the anchor alarm. For me it kind of depends on where I'm anchored, how much room I give myself. Also what I do often, is leave in on for an hour or so after anchoring, and use the track function. This will give you an idea of your swing and often give a good idea of what distance to use on the drag alarm.