http://www.addicted2decorating.com/second-roman-shade-finished-plus-a-tutorial.html
http://www.ohohblog.com/2016/03/sew-roman-blinds-shades.html
Alternate: no rings, just eyescrews in the end of the dowels.
And, channels in lining fabric ONLY, so this would work with a large print.
http://wipster.blogspot.com/2010/06/avoiding-night-time-peepery-with-roman.html