Thanks again Glynor for all your help with this, and the great information.
I suspect that my problem was that I was using the same share (J:) that the Library was on, so MC was probably trying to update while it was busy, and doing it all over wifi just bunged it up too much.
I think I've decided that I'm just going to move the Library to the HTPC, which is hardwired to the unRAID box via GB Ethernet, and deal with the extra power usage of having that machine on all the time. I believe I can still let it sleep when not in use, so I'm probably not giving up much in doing this. It assures me the library is being served from the fastest drive, and is connected to the media with the best speed I can get.
I'll hope that if I try to open MC on the Desktop using a direct connection to the Library (not via a client request) that it will wake the HTPC. If not, I'll figure out how to create a 'script' that will send the wake command before trying to open MC.
I'm still recovering from having my jaw broken and reset 11 days ago, so I'm not super motivated to do much of anything currently, and I suspect it will take me a little while to get all this done and tested further.
If I still see issues with speed, I'll certainly come back and post my results of your suggestions.
HDTune is free? I see they charge for it, so maybe there is a free option also; I didn't look that hard. I'll look again.
Thanks again for your help.
PS, I'm still looking forward to trying out your library if/when you ever get time to finish cleaning it up for public consumption