Overlay mount at btrfs

I multiboot several distributions which are at separate subvolumes. They are stored in a not standardised layout. I have some subvolumes which I want mounted in a layered way. I prefere to use aufs . For example, I want /home/myname to be mounted at every dist . I also want some generic /use/share/bin to be overlay mounted with the dist-specific one. There are to many subdirs/files to maintain symlinks instead of overlay-mount. Due to cow-issues between btrfs and layered FS , I understand that I should not use layered fs together with btrfs. I figured out that I maybe could overlay-mount read-wtiteable ext4 images , which resides on btrfs-subvols. I suppose I then should disable CoW for just the wm images. In that way I could still snapshot the subvols which contains the image-files. I mainly would like to know if there is better solutions to combine btrfs and layered fs .