I studied this a bit.
I feel that the brass bushing should be installed from the bottom. This will provide a wider surface against the wood. If installed with the flange toward the screw, the thinwall of the brass will cut right into the wood, eventually becoming loose and rattling. With the flange against the wood, the screw head is against the thinwall side and a sort of captive spool is created. The screw head will not be bothered by the thin wall edge. The brass bushing also keeps the rubber grommet snug in the servo flange.