I think you'll be best off on a specific Rickenbacker forum but be prepared for extreme nerdiness on the specifics of the bass.
Basschat is normally good but you can't post Rickenbackers for sale on there, though someone might post a wanted add that you are allowed to respond to.
Bass resale seems to happen at a higher price point to cycling; you could probably ask for 75% of retail & see how you get on then let them negotiate you down to 70% (though go for higher like 80% if you think it's in really great nick).
I think you'll be best off on a specific Rickenbacker forum but be prepared for extreme nerdiness on the specifics of the bass.
Basschat is normally good but you can't post Rickenbackers for sale on there, though someone might post a wanted add that you are allowed to respond to.
Bass resale seems to happen at a higher price point to cycling; you could probably ask for 75% of retail & see how you get on then let them negotiate you down to 70% (though go for higher like 80% if you think it's in really great nick).