Before I made my
most recent post in this thread I copied the contents of my calibre 64 bit installed config folder to a fresh Calibre Portable\Calibre Settings folder.
Then I started calibre portable (by hitting enter on Calibre Portable\calibre-portable.exe in Windows explorer). According to calibres status line, and Windows Task Manager and Process Explorer I was running calibre 64 bit.
I restored the Calibre Portable\Calibre Settings folder back to its install state.
Then I started calibre portable (by hitting enter on Calibre Portable\calibre-portable.exe in Windows explorer). According to calibres status line, and Windows Task Manager and Process Explorer I was running 32 bit calibre via calibre-portable.exe
From that I concluded you
cannot copy the entire contents of a 'regular' configuration folder to Calibre Portable/Calibre Settings. I suspect you can copy most of it, but I am unwilling to conjecture on what you can and cannot copy on an item by item basis.
BR