One very easy trick to try is to take the intermediate air bleeds out and see how it runs. Holley left them out on at least one version of the 3 circuit 4500 so there is some history behind that thought.

It would be helpful if you had a wideband when you try stuff like this but even without a wideband you should be able to tell if you're on the right path by how the engine sounds.

A set of billet metering blocks is probably your best investment if you want to dial the carb in yourself. Otherwise you can send the carb in and get it sorted out for you.