Paul - I use this configuration for one of my guitars and I buy singles. I worked worked for some time with the standard string guages as set for the high octaves of a 12 string set - but found I like a heavier G and D strings. So now, that I have setteled on the guage strings I prefer, I go into my local Guitar Center music store and buy 6 of each - I buy individuals. It works out fine - but I do suffer some uneven berakage in the Texas summers ... so I'm apt to have to replace G's B's or D's more frequently.