For EWS, 1-2 flares on PGM6 is handy. Don’t worry about chaff or CMs much at all. You can have a very long and illustrious career in BMS without dropping a single countermeasure. It’s dealing with single digit % points on enemy Pk at the best with the possible exception of older heat-seeking AA missiles. If you spend more than a second thinking about it during an engagement that second is probably better spent doing something else more effective to counter the threat.