Steve,
I also have my sensors in the rh chamber for a couple of reasons, mainly because the water lever there is more representative of the actual water level, on the lh side it is influenced by the fine filter, if this clogs up the water level drops and you will be adding more water in when it isn't needed. The other reason is as Mike says, it would be a pain to move it everytime to clean the black sponge. There is also an advantage of it being in the rh if the fine filter does clog up badly, this causes the water level to rise in the rh chamber and sets off the overflow alarm on the tunze.
Good luck