@Joulinar Thanks for your reply.
I’ve had a look at option 2 but that will copy all the logs to SD.
I’ve decided to use the /run/ directory which is also mounted on tmpfs (the ramdisk) but isn’t affected by the cleaner script and whose content is only lost at reboot. I then have a daily cron job run under my user to move the files from ram disk to a directory on the SD card in my home directory.