1. It doesn’t use the “Bow Offset” when pinging the line, so position the boat to get your watch as close to the mark as possible, then ping. I usually cross the line close to each end and ping as I cross the line, after all, the length is not critical, but the bearing created from the line joining the pinged marks is.
2. Nope, just make sure you select the correct button (I get confused as well!)
3. Nope – it just over-writes that one end, so you can re-set the pin after the RC has moved it.