I used 7 yards of 3mm (momme) 45" wide white silk gauze from Dharma Trading. About $18.
I cut the yardage into 2 equal lengths (3.5 yards) and sewed the long uncut edges together, making a tube. I sewed a channel on each end and gathered the ends: at the foot end with a short piece of very light shock cord (so it would stretch to get over the ring on my suspension but still keep bugs out) and the other with lightweight cord and a cord lock.
It remains attached to the hammock at the foot (stores nicely in a bishop bag) and is deployed by pulling it over me and the hammock and cinching it up while inside the net. I use a structural ridgeline on my hammocks, which keeps the net off my face.
The silk is very fine and is very easily snagged. I am quite proud that I managed to deploy it in a forest of Ponderosa Pine and not get it snagged on any lurking pinecones. I don't know how long this net will last but it will do for now.
I like a lot of sag in my long hammock, so this net is not really wide enough to accommodate that sag. I had to lengthen the ridgeline to make up for the width issue. The next net will be made with a diamond shaped gusset in the center of one long seam to provide "butt room".