I made my curtains myself, too. I used a fairly pricey material from a fairly pricey specialty/upholstery store so I shopped around a bit before finally settling on an off-white medium weight cotton material at a regular yardage store (...also, sales happen a bit more frequently there, thus providing an additional incentive.
) (I made sure to wash it before using it...didn't want any weird shrinkage later on.) I've been very satisified with the privacy offered by the two layers without having to go to a heavier liner BUT my main drapery material WAS extra heavy and provided the weight I wanted.