(Not foolproof, but) you can (specifically) assign drive letters to specific Flash drives such that they will end up being (essentially) static.
Yes, that is what I do for hard drives "all the time". And what causes some problems with duplicate indexes when Win does not know the letter anymore. Then it assigns another letter and Everythings scans the drive with that (wrong) letter and - after I have changed the letter - it scans the drive again with the other letter.
You can do that manually, through Disk Management.
(Assign letters "high enough" such that they're not likely to result in collisions).
I am afraid, there is no letter left. So "high enough", at the end, the second half of the alphabet or so.
Or with something like, USBDLM - USB Drive Letter Manager for Windows.
(I've not actually used that.)
Many thanks for the link. This I could use to assign the drive letters? I once had used that program, I mean to remember it somehow was...I could not cope with it somehow. I guess, I cannot use it intuitvely.