Tuning a Proform/Holley carb, what parts and tools?

I am watching the Holley tuning video, and it was saying if you don't remove some fuel from the bowls first you will bottom out the floats. Does this not apply to this carb because you can lower floats with the engine running?

I have heard conflicting info on where the fuel should be in the window. In the middle or at the very bottom, which is it on a Proform/Quickfuel?