Originally Posted by
pdlamb
...No need to pfaff about getting a rack-mounted tail light (which seem to be getting a lot scarcer in the last few years). ....
If you have a seat stay light mount, wrap a bit of rubber strip from an inner tube around the rack to make it a bit bigger and then put the seat stay mount on the rack that way.
I typically use two taillights when touring, most of the time one is a backup but in fog or heavy overcast or rain I will have both lights on.