Looking good
Using the spokes for the rudder will be fine, as they are quite strong.
Can't see whether you are using stringers to put all the gear on, but some of the snake will need to be fixed to them to keep them tight, as they are very flexible (you can tie them in knots and they still move), just fix them in until a couple of inches away from the carb, and a couple away from the radio box to stop them flexing. Once secured, they are almost bulletproof connections.
Attached is a
very accurate child like drawing of what to do with the connectors (clevises), You need to get about half a centemeter of silicone fuel tubing (shaded), and put it on some needle nose pliers, slip it over the clevis, then take the pliers away. this will hold the clevis firmly shut, and will not let it open while the boat os moving (at the stevenage race this happened, so the person driving had no throttle control and had to crash the boat). To reopen the clevis, simply slip it towards the back of the clevis.