Thanks Matt for getting back to me.
In trying to undertake your test I have been reminded once again of what seem to be basic flaws in the watch's hardware. There is 16GB of music on the watch and all systems seem to have problems connecting and reading the watch. Windows takes ages registering the files and JRiver goes into an long running "working" status when I try to make the device available to JRiver. If I do get to the end of J-river's process the watch usually disconnects and drops off the drives list. If, alternatively, I do a "send to" of an individual audio file to the Garmin watch I get an unending "loading handheld" message. This makes doing simple tests like you are requesting near impossible. I have spoken to Garmin this morning about this and they say there are no such recognised hardware issues with the watch. Neverthless, they have agreed to take the watch back and assess it. I will go through this return with Garmin and see where this takes me before making further judgement about JRiver's sync to handheld for this. So, this post is on ice from me for now. Sorry for the change of direction, Regards, Michael.