I was also testing wearing my SPOT unit on my left shoulder. I forgot about it until my sister's friend asked what was blinking on my shoulder. Every transmission was received.
My SPOT Track >>>

The shoulder is the best place because the sailors shoulders always have clear view of the sky and if the skipper is wearing it, it will stay fairly dry. I found a local place that we can rent the SPOT units for about $40/unit for the week.