Doesn’t matter. I’d place it on a dedicated drive with all your images, presets, etc. That way you can clone that data to any number of drives quickly and easily. You could take that drive onto any machine that has the LR application and have access to all your data.
I've consolidated the catalog into one single master catalog located on the second SSD. Will set the LR Backup to my HD which is on a mirror drive and is also backed up regularly.
You said "clone" rather than backup - any particular reason ??