what's the best way to attach a prop?

the spinner i bought came with two sandpaper washers ('grip washers') which, the diagram on the packaging indicated, should be placed on either side of the spinner base.

i did this, but while testing/running in the engine, the spinner would rotate relative to the engine (the engine-side grip washer was disintegrating). so, i removed the grip washers and it seems better (the spinner doesn't rotate relative to the engine now). however, now i've noticed that the prop is _slightly_ deforming the plastic spinner on either side of the prop holes. ie., the prop itself is now moving relative to the spinner.

the toothing on the spinner base is effective to prevent the spinner from moving. but there's no toothing on the aluminium spinner base to engage the prop. ie., it's a smooth surface between the prop and the spinner base.

should i tighten the prop nut? i think it's already quite tight. should i put the second grip washer back in? should i glue the prop to the spinner base?

cheers

c.