RE: Throttle Sleeve, ACE OR COX Setup??
Ok, here's a few things that you might want to try.
Firstly, Z bends don't always have to be axial, so to get around your fouling issues, maybe you could bend the toe of the Z bend away from what it's hitting to alleviate the problem, or rotate the toe 180˚ to make a U bend instead. The toe on the Z bend is merely there to provide a means of keeping the pushrod attached. If you think about the first bent leg of the Z as doing all the work, and the second as the keeper, I'm sure you'll come up with a satisfactory solution.
Also, nylon clevises and searingly hot exhaust systems are an accident waiting to happen. Don't use it unless you don't really want a throttle after all.