if im correct once you make your flash drive to boot windows
you cant use it for anything else
even if it would be 32gb it would still hold only windows
No, that's wrong, you can still copy files from your bootable flash drive, you just made it bootable, that's the only difference. The ability to save files from your flash drive is not taken by making you're flash drive bootable, just don't delete some files from it unless it is your file.