I have a linoleum floor in my coop and 3/4 of it is covered with sand. I do have a poop roost as well. My nest boxes had shavings in them and the girls scatter it all over the place. More work than cleaning the sand. A BYCer mentioned nesting pads from eggcartons.com. They are not like the ones you purchased. They are 13 x 13 Excelsior Nesting Pads and 20 count cost $19.95. I just added them to the nest boxes this afternoon. I will see how the girls adapt to them. Also will see if there is any mess as I was told there shouldn't be any.
The ones you purchased, are they soft for your girls to sit on?
http://www.eggcartons.com/images/EP1313.jpg
This is what my nests look like after an egg is laid. Shavings almost all gone. I have indoor/outdoor carpet underneath so the egg doesn't get broken.
Could not find a pic with the messy floor. Seems I only take pics after the cleanup!