what is it you are worried about curling? the papers? they stay flat- the fabric? it stays flat too...you cut your fabric with a seam allowance- fold the fabric over the papers, baste around the shape --for pieces that large I run a running stitch all the way around the fabric- then pull tight around the shape and tie a knot to hold it. or use running stitch along a side, fold the point, take a (holding stitch) turn the corner- continue with running stitch to next point, fold, stitch, turn continue- works well. I have used 3 1/2" diamonds, and am currently working on 3" triangles- I will take a picture later of one of my triangles to show you what I mean. I have a friend who uses the starch method for pieces that large- which seems to work well too- I just prefer the stitching over all the time at the ironing board. * she sprays starch into a dish (plastic container lid works well) then places the paper piece in the center of the fabric 'paints' the edges of the fabric around the paper with starch and using her iron folds and presses the edges in place- then joins them as normal right sides together, whip stitch - removing papers as she goes- it does seem to work well- some people do this with glue too- although that seems like it would be hard on your papers.