Don't know about the ZX shocks. I went with the mid-grade Penske with the 600#/inch spring (I'm ~200 in gear) and the .90 kg/mm fork springs per Nick's recommendation. Excellent result (7.5 wt fork oil by the way- should have used 10). I took about 2/3 turn out on pre-load from the as-delivered setting, and went down 9 clicks on the rebound. The difference between the updated suspension and the stock is night and day. With the stock suspension, the bike moved around a lot if you hit a bump while leaned over in a turn. Even in a straight line it didn't feel great as it went over bumps. Now it is much more stable, particularly through bumpy turns. Well worth the expense- the bike isn't limited by the suspension now. Another benefit is that the front doesn't dive with the slightest touch of the front brakes. Nick knows his stuff.
I have the Penske Stolec shock with 600 lb spring. The 650 lb spring was too much for me in my advancing age. Running wide open on compression damping and 24 clicks open (out of 33) on rebound. Works nicely. It has solved the problem of the expansion joint on the freeway and does quite well in the woops on 24th street. 10 weight oil in front with stock springs, screw open ~1 1/4 turns.