A couple of years ago I bought some replacement bulb holders. They didn't want to stay in the sockets and would pop out. Tried another vendor...same result. (one vendor in US and one in UK). Took a screwdriver and added a bit more bend to one side of each tab.... which made them fit properly. Too bad they just can't be made correctly
For improved grounds, I've seen people wrap bare copper strands around tabs and than to a ground points. Some people have been able to solder the inner ground tab to the outer ring. I wasn't satisfied with my soldering, so I took a spade connecter and glued