Sorry - I do not want to offend you in any way. Its just - the three options you suggest do not solve my problem. That is why I asked the question in the first place.
You do not want my feedback or my help and you do not consider any of my suggestions seriously. Ok fair enough its your project. I won't bother you again.
To show you I am just a caring supporter of Calibre, which I love, I will donate USD 30 with paypal when Calibre works over a network drive (single or multi user).
Thanks again and good luck with the next version.
ps: you just could have directed me to github:
https://github.com/kovidgoyal/calibre/issues/26