If you milled the top of the plenum flat, then you do not use the wedge spacer.
The wedge spacer is so that you do not need to mill the intake manifold to be flat.
You do one or the other. Not both.
On the carb, just use a normal Holley 4v carb gasket. The channels are for the balance tubes milled into the base of the carb throttle body.
Leave them alone.
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