I am using the Bass floor spreaders in my cages. I put two on my 2'x4' cages for breeding does and one on my 2'x3' cages. They are working marvelously, and I wouldn't want my cages to be without them. The Bass floor spreader is round and doesn't let urine sit on it like I think the square one from Klubertanz could. I didn't want any extra chance of the floor rusting out with the flat one.
Zip ties are what I used initially to attach them, but recently I purchased some of the 3/4 inch c-rings from KW Cages and those work well, too.