The floor should be the number that you don't feel bad about accepting. That indeed includes your perception of alternatives. If your floor is higher than what you're going to get, you'll miss a few jobs and then learn that your expectations should be lower. That makes the new floor acceptable.
There isn't really a shortcut, because if you feel like you've accepted an offer below your minimum and never applied for other jobs you'll feel like that forever. Which isn't a good foundation for the next years working in the role.
> If your floor is higher than what you're going to get, you'll miss a few jobs and then learn that your expectations should be lower. That makes the new floor acceptable.
Right, but this process is only acceptable if you believe that you have more than a few options in the near future.
There isn't really a shortcut, because if you feel like you've accepted an offer below your minimum and never applied for other jobs you'll feel like that forever. Which isn't a good foundation for the next years working in the role.