Hummm, help I'm lost with suspension

I have a friend who has a 99 with a .43/5.2 combo with stock valving and it works great. I'm 205 with gear and run 5.4 and .44 with MX-Tech valving on my KX. With the 5.4 and your weight, you'll not have the spring compressed on the shock enough which in turn will effect how the bike turns, how it resists bottoming, and how it will soak up stutter bumps. The fact you can't get the correct sag measurement is a sign it's too heavy a spring.

A .42/5.2 combo, for your 170lbs, I think would be the ticket, but then you'll have to probably get your valving sorted out. That's ok, that's what those shops are there for. If they're good, they will modify it until you like it.

Good luck!

I'd say valving needs to be changed

The place I get my suspension done has no problem with revalving if it didn't feel right the first time. I like mine pretty plush in the braking bumps etc. but need it to soak it up on the hard landing and g-outs. I weight 200 lbs. or so.
The most important thing is to be able to communicate what you like/dislike about the setup so they can make the necessary adjustments.