What would be the highest loft of a batting that it's feasible to use with a domestic machine? I've always stuck to the same type - bamboo or bamboo/cotton but have to say I've made quilts I think I'd have preferred more puffy but without excessive weight caused by doubling the wadding. I'm not keen on using anything that isn't a natural fibre.

Is there any reason you couldn't layer two battings to get the needed thickness?