I too love wool battings- they needle beautifully- hobbs 80/20 is a very nice batting for hand quilting, I have not tried silk but would imagine it to be fabulous---I think the answer should really be based upon the quilt. are you making an Heirloom quilt? if so, go with silk or wool- something fabulously luxurious- if it is more a quilt that will be used often- nice but not necessarily one to be more of a 'show piece' than an actual used quilt go with a cotton blend or cotton. one without scrim (like warm & natural- not a good hand quilting batting)