My 12 string set (for around 35 years!) is as follows (w = wound, p = plain):

1 & 2: 010p

3 & 4: 010p

5: 023w

6: 010p

7: 030w

8: 012p

9: 038w

10: 018p

11: 048w

12: 027w

Admittedly the D'Aquisto 760 sets I have at the moment (I buy direct from JHS here in the UK) come with an 009p high G, but I substitute an 010p. I prefer the Kaman bronze, but no-one around here stocks them, and Kaman aren't interested in dealing direct for a box of 12 sets...