The manufacturer suggested a range for a nominal system taking into account variations in cable impedance/capacitance. I would play within the range suggested and see if you have a sonic preference. If not, in the long run, I have always found, in my system, that increasing the load on a cartridge (meaning lower Ohm settings) is again, in the long run, what I have found I usually return to. Be confident that you can hear your preference. Remember there is no harm that can be done by choosing a "wrong" setting.
I had a Chinook (traded up to a Steelhead) and found the load settings to be easy to set.
I had a Chinook (traded up to a Steelhead) and found the load settings to be easy to set.