only one "best" way and thats to get them welded up and boot lid resprayed. otherwise find some black grommets that'll fit. OR swap bootlids with car of same colour without spoiler.
mine was welded up, havent got it back yet. its being sprayed tonight/ tomorrow re fitted to the car thurday night (finally!) then the car is getting a full buff on friday.
i remember someone mentioning going to a car dealer to swap boots.
Apparently they don't mind swapping as the price of their car increases so its a win win situation. Don't know how true it is but lol