Unfortunately, modern muslin is a rather more thin and fragile fabric than the flax homespun used in ye olden days. The upside - very light and cool. The downside - not a perfect sun blocker, and of course quite translucent.
I did, however, do some repairs and a nifty alteration. At Faire each year there is always the issue of carrying capacity and adverse temperatures (sounds like D & D, no?).
I had a smart thought, I own a camelback with 72 oz. of water space. But, it came with a bright blue and yellow pack, not quite period unless your period is the 1980s. So I found the only part of my costume with space in it - the bustle. Badonka-donk ass + hydration = awesome.