I have a similar system to yours although mine is open 12" shelves on the wall and I keep all sizes of a similar color together (except scraps). I separate the fabrics by type as well, corduroy, home decor, fleece, flannel, tapestry, velvet/suedecloth, brocade/satin, batik, regular cotton.
And like you I reorganize the stacks every time I'm looking for fabric to use for a particular project. Isn't it fun!!!
In general I do not use boards. I do have the rolls for the velvet. If it is 3 yd or less I prefer to fold it in half lengthwise, then do that again, and finally fold so that it fits the shelf (however many folds that takes). It seems to me like the boards would take up space that I could put more fabric in. LOL!