ok so i was researching cathedral window quilts , cause eventually want to do one.. muslin....i see at the stores several kinds.. so my question is... how is it different from regular quilting cotton, as it is 100 percent cotton itself, and why not just use cotton instead of muslin? what are the bennefits of muslin? so what are the pros and cons..i want to learn everything about muslin so let me have it... thanks!!!