I thought the CZN only came in a 4wt in the 11' length?
Try your question and searching here: Gear Talk
it is mostly east coast guys.
I have a 2wtESN, 10/3 and 10/4 Zeniths, and a 10/4 St Croix High Stick Drifter. The ESN and HSD are for tight lining and the Zeniths for casting. The anticipated weight of my flies dictates which two rods I take on the water, the pace of the current plays into this, but not the size of the fish. If I can wade waist deep without working due to the current I take out the lighter two.
A 3wt seems to be the most versatile and popular weight of the typical rod models if you are going to have one rod dedicated to tight line/hybrid euro methods. If you may use it for indicator nymphing at a distance, a 4wt would likely be better.
It sounds like you have other rods as well, so I would go with a 3wt in the lower priced offerings (CZN, Streamflex XF2, Fenwick Aetos, Cortland Comp), or if you were really worried about the rod's stated weight, a 4wt specifically designed for the application with the latest materials like a HSD, ESN, or Loomis Nymph. I have never seen a CZN however....
FWIW I am completely in love with my St Croix.