Float level becomes really important when using the top hole, because if the accel pump is above fuel level you will get air mixed in with the pump shot leaning it out. The nozzle only controls timing via length of shot, not pump volume which is controlled by which hole you are using.

If you are using the stiffest step up springs it will go into power mode faster which may be why it's going rich. I always use the orange springs but I'm also at 5000' so I get about 14" of vacuum here. You may want to try the pink springs first for your application.

There's a couple good pages in the Carter book. Let me see if I can scan them.