I don't think I'm going to be very helpful. I used them on a much younger baby (5 or 6 months) and they were a nice fit, but did wick.
I had the cotton covered version, which was lovely, but not the most reliable. I think the PUL solid colours are more reliable.
Have you looked at my nappy review blog the piccie is the HH that I had. There are ten comments, so that might help a bit.
I just put my 3 year old into cloth at night, didn't use happy heinys, but I did get a custom made lightning mcqueen wrap made which went down well! So well in fact that he only wore it 3 times before going all of last week with no nappies!
I did look into heinys as they have all the nice prints and similar to a disposable for ds1, but I was told that the print pul wicks after a couple of hours? Perhaps it would be an idea to contact one of the online sellers and see whether they wuld recommend them? hth!