I just bought two of every led I could find from every seller, had apx 10 sample bags in front of me, and spent a few days mucking around til I found the perfect choice/choices.

whiote in white inserts, red in red, white in yellow (never yellow/looks awful) and match colour of insert to colour of led.
purple n pink inserts also like white as well.

flat top white is best all round, or red, green etc, but flat tops are best for inserts.
I leave flashers original or u go blind.

I found 5 in 1 leds too bright, again blinding.

only other leds I buy are the toothbrush sideways looking ones for inserts that have a pcb mounted sideways.

Re buying in bulk, I see terry from pinball life. buy 100 a time n watch the money come right down.

mark from melb does deals too if u screw hard and ask for the same price as terry I think I buy the toothbrush ones from cointaker, but again in BULK or its too expensive..

I just bought 1000 (one thousand) of each type n colour I wanted n got a huge discount. spent a few grand, but it was the only way to led out 40 machines.

then u need valium after all the farking around putting them all in.lol