my best idea would be like
sites 1F-3F could be used as 1,
site 4F-6F could be used as 2
sites 7F-9F could be used as 3,
sites 1T-3T could be used as 4,
sites 4T-6T could be used as 5,
sites 7T-9T could be used as 6,
sites 1R-3R could be used as site 7,
sites 4R-6R could be used as 8 and
sites 7R-9R could be used as 9.
the problem would be some sites would be ridiculously OP at their slot like
steps of edoras at site 7 or bridge of khazad dum at site 2, but it seems like it could work