I'm similar weight as you and I've tried a couple different combinations on the rears.
Stock springs all the way to 5 was too soft.
Stock springs with hygear torsion spacers, better but still bottomed out more than I'd like.
HD 270/271 doo springs with torsion spacers, WAY too stiff, no ski lift, harsh ride.
HD springs without spacers, slightly less stiff, but still not enough ski lift and hard ride.
I would go back to the stock springs and torsion spacers if I did it over again. The HD springs from doo are too stiff. This was on a 154, a 165 may not be as stiff or harsh since there's more leverage with the longer rails.