[phil_ga]

Thanks BetterRed for the detailed suggestion! As you guessed my settings were already geared along your lines. This works beautifully for windows explorer! This feature is an excellent compromise to what I was after in the first place. Thanks for suggesting it!
However I don't actually use Explorer, but Directory Opus - a file manager replacement. I have used it for almost 10 years without a fault but it refuses to recognize the drop from calibre for some reason. It has never, in all that time, refused a regular file command that works in explorer. So it may be a bug with DOPUS, I will go ask them if they have ideas.

I still think my original suggestion would be best (for me!), drag EITHER the mobi OR epub directly from the "Format section" to copy whichever version you want thru a drag and drop (but your idea is a good improvement on my current options)!

Thanks mrmikel - I am well aware of not playing with the library folders and understand the problems (but thanks for the warning to newer users). My way around this is very simple - just have a dummy library with nothing in it, solely for file conversions. Then you can screw around with library folders all you want. Problem with library folders is the awful file name convention. The beauty of the main program is that you can control the file name format using preferences for files that are saved out of the library. So its always better to go via Calibres export functions instead of the library folder (as you are suggesting in the first place).

Thanks theducks, but as I was trying to say, I am aware of the export buttons and was looking for a drag-and-drop solution as it does not involve copy/paste for the destination path - too many steps to do over and over again each day.