I bought XL punky for 'Snakes N' Barrles' Pickles. You can't weft around the top, it does have that dense knotty stuff at the bottom. The area is a little bigger than the standard skin top cap but after that section if you want to add wefts there's plenty of room to do so, although really you don't need it.

I'm actually gonna post a picture or two of it.