give the bps teaser tubes a try they're 2 3/4" , i rig them on a small jighead with single wire weedguard. i think the heads i got now are arkie heads i got at wal-mart 1/8 oz.
I recently read a small article in field and stream that followed some study about bass and crayfish they prefer.
smaller ones are easier and faster to turn into protien, with less effort, but in extremely rocky areas the little ones can get back in the rocks faster and are harder to catch, so then the fish switched to larger craws.