88 sts and fingering sounds about right for a baby hat. I think the same 88 on a size 7 or 8 needle and worsted weight may be about right.
Evapche, you need to figure out your sts per inch with the heavier yarn and the needles to see how many inches 88 sts will give you. For an adult hat you need about 19-21" worth.
sue- knitting heretic