Frankly, I would have purchased the baskets first, then built the shelf.

Not very helpful, I know, but as you have found out, baskets don't come in all

shapes and sizes.

Thanks. I really wish for wicker. The shelf is high enough a few scratches don't bother me. Finding 3 of the same size and material is a challenge.

Find a local basket maker and commission them. You'd end up with the size, material and color you want.

Try the Container Store, Crate and Barrel, Pottery Barn, and West Elm. All of them have a pretty large array of bins and baskets in different styles and colors.

Custom sizes at amishbaskets.com

I’ve ordered custom sizes and they are nice

They look like wonderful baskets.