I like to use ziploc bags to keep things organized. The ziploc bag doesn't need to contain only one item type. I have one that has 10 4x4's because that kit has lots of 4x4's, but another ziploc has a couple 4x4's, a 5x9, gloves and a triangle bandage. The ziploc can be organized as needed, mix and match. It's nice if a FA bag has the organization built in, but even with those bags a separate ziploc might be nice to carry items to clean up and glove up before getting into the rest of the FAK.
YMMV