I think using a silk bonnet/cap and/or pillowcase (I use both) really helps with second day hair. My hair doesn't seem to like anything added to it except a drop or two of a light oil (camellia) or something like SS Emolience to smooth a bit. Right now I'm using the Emolience mixed with a drop of oil for better distribution. Gives a nice shine and tames any frizzy bits. My second day hair is pretty good; third day is sitll a work in progress.
Former longhair, now CG, living in N. California where the fog meets the wind
3a/b, fine, normal porosity/elasticity, high density
Conditioner wash and style, sometimes with a dab of BRHG.