I carry separate FAK & PSK. That doesn't mean it's the best way, It just means that I'm a packrat. I carry my complete (?) PSK in a Trangia Mess Tin with only minor First Aid Items. I carry a separate FAK about the same size as the Trangia kit. Why? for one thing it's fun when my wife gets a minor cut and I unroll my FAK, pull out a scapel and ask how much pain she can take. Her loud reply concerning my ancestry helps to calm her down so I can use some iodine and a band aid.