Thank you for your tips, Robert! :-)
I have to try this out, but need some time to rename my files... :-)
I didn't know there was a maximum of 250 styles per directory... (I have experienced many minutes (2-3) with "hangs"; The Disk-in-use-light lights up and brights constantly, while nothing can be done (Message on display: "Checking")... Maybe this is the reason, I may have more than 250 styles in the folder...
Have a nice day!