The metal push rods in your Nexstar require a plastic guide tube that needs to be supported at both ends at minimum. Supporting it in between is helpful too. This will likely require some modification to the fuselage, adding balsa braces, etc. (all very doable of course) If you are ready to take on that sort of modification, fine. It is your plane after all. I figure that there is no reason to fix what isn't broken. There is no need to do the additional work. The wooden push rods will get the job done fine. If anything, I'd just make new wooden dowel push rods if the ones supplied with the plane were questionable. I subscribe to the keep it simple philosophy.

My World Models Rambler 45 uses a wooden dowel for the elevator. It has two wires that "Y" at the end to control each half separately. I was leery of this at first but I decided to run it. The plane is extremely fast and very aerobatic. There has never been an issue with fluttering, binding, flex or anything else. It works great. My Phoenix Sukhoi used dowels for both elevator and rudder. It was a VERY aerobatic plane and there was never an issue other than me dumb thumbing it into the ground. Your Dolphin isn't as advanced as either of those planes. It will be fine.