Here is my sticking throttle story. After have my carbs replaced with 40 Webers by Vintage, my throttle would stick any time I was slowing to a stop. I would have to tap it a few times to get it to finally idle down. I couldn't see anything wrong, so I replaced the cable, but it still stuck. Finally, I took the carbs off and they functioned fine with the throttle slamming shut like it should. So I put them back on and tightened them and could see that without the linkage, the left one was the one with the problem. So, loosened the the two nuts and the problem went away. Tightened them again and the problem came back. Took the damn thing off and inspected the manifold and could see that it was not machined perfectly flush, so when I tightened the nuts, it would bend the carb body just enough to cause the throttle shaft to bind. Kirk sent me a new manifold and that solved the problem. I am still wondering if just putting a slightly thicker gasket on might have also solved the problem and if you have not tried putting on new gaskets, I would give it a try. If it works, then you can get rid of the extra springs.
Troy
PS. It's July and my rear end is showing. Check your calendars.