I have a couple of them both minky and micro. I don't prefer any one over the other it's just the minky is more of a show off nappy.

I'd say go for the smalls. They are quite a generous fit and Caleb can still fit his mediums.
When I first got some I got one med and one large as I was unsure of the size. I don't mind putting one away for later. Caleb has worn the large a few times but as it is still a bit big around the tum it's only in an emergency