losing a thrust bearing most likely fried the shoe. i lube the thrust bearing with just a few small blobs of Mugen super grease about every 15 minutes of runtime- after three hot lap sessions or every other heat and definitely before any main.
i'd stick with the super-hard spring or MSR 1001 spring and the yellow shoe. the yellow shoe seems to be the best all around shoe unless you are on a track with no bite- then go to the black shoe. the grey shoe is next best after the yellow in term of a good all around shoe- at least for me.