Gramfel, are they in squares or just the fan shapes? If they are fan shape, you could applique them onto squares of white fabric and put them together that way. If they're already in square blocks, you could put them together with or without sashing (depending on how you want them to look) and yes, you could stitch in the ditch or just around the outside edges of the blocks if they're not too large. You want to check on how close your batting needs to be quilted. Some battings need to be quilted 2-4" and some can be quilted as much as 10" apart. If you don't plan on using the quilt, but only want to display it then how far apart you quilt isn't such an issue. Hope this helps, rather than confuses you.