How often is a bug net really necessary? They seem to be the heaviest part of the set up. I usually camp in the southern Apps. My tents had bug nets and my HH has one but I've tarped a few times w/o and was fine after using bug spray.
I haven't used Permethrin, but if clothes and hammock are treated and you're using a max DEET spray, wouldn't you be OK? I heard that black flies are devils with wings but I've never had to deal with them.