rear hub - getting seated

Just put new rubber bushings in the rear wheel. Having a hard time getting the prongs on the back of the hub to fully seat.
Should i get the old mallet out and smack it down into the wheel? don' t want to hurt the new rubber bushings too bad.

Have you tried a dab of "rubber" grease? (silicone grease)

The factory cushions tend to sit proud of the hub flats but should seat fine once axle nipped up if you can get it to assemble that far. There is a slight tapper narrower into bottom of the cushion hole so rubbers tend to jam up a bit with full seating.
When I make my own from fiber enforce conveyor belt I nip em down till they just hold off seating ~1/16". I don't like to grease em as it helps mount if the cushion friction help hold in place a bit while aligning to nip up. Whole darn rear feels all misaligned and sloppy till split axle gets well tightened, while holding brake to center that best able.