The only craft store netting you are likely to find is a dress fabric for proms and such. Don't remember what it is called. It will stop mosquitoes but not no-seeums. It is light, but not durable at all. It is usually cheap, though, so you can experiment.
For a diagonal lie, you need a good bit of sag and more sag means more net. I use two widths of 54" nanoseeum from Thruhiker, hemmed together along the ridge with a casing to run the ridge line through. The casing keeps the net from sliding off one side. Pockets on each side will hold water bottles or shoes to keep the net from flying up in the wind. Hand stitch the ends after you have tried pins to see where to stitch with the hammock set up and you in it. Velcro is not so good on the ends. It snaggs and tears net. Long running stitches will do the job, are easy to remove and quick to replace if you ever have to. However, you can still take the hammock apart without removing the stitching.