I've been toying with the notion of hammock camping and even tried (and returned) a Hennesy Hammock which I did not find comfortable. I'm now considering making my own and am interested in input.

Hammock
I'm interested in something along the lines of a Speer hammock...
Question 1: what is the lightest reasonable fabric? I weigh about 180 at winters end.

Q2: I'm thinking of a bug net that is basically fixed to a ridge line and then draped over the hammock edge without Velcro or zipper. Any experience with how well that arrangement actually works? Think Maine in blackfly season...

Under quilt:
I'm also thinking about making an under quilt. There's plenty of advice out there so I won't ask you to do my research for me, but do have a question about material. My thought is to use a single 0.75 inch layer of Climashield for insulation, 0.9 oz momentum for the outer shell and NOSEEUM netting or the lightest silk that I can find for the inner shell. How much stress does that inner shell need to take? My assumption is that it serves only to stabilize the insulation...

My target temperature range is mid-40's. My thought on adding insulation is to sandwich the foam that serves as the 'virtual frame' for my pack between hammock and under quilt...possibly hanging off the hammock with some very simple toggle arrangement. Again - any thoughts or experience to guide me before spending $$'s and time would be appreciated!

Thanks!

My advice would be to make a "test" hammock from some cheap nylon fabric, to see if you can get comfy in it, before going to far with your home made system.
Mostly because the good home made versions are similar in comfort to Speer-type hammocks, and I consider the Hennessys to be more comfortable than Speers, and more bug-proof. If you couldn't get your Hennessy to be comfortable enough, It's unlikely you'll get your home made ones any better.
I have 3 Hennessys, one Speer and 8 home mades. The roomy Safari Deluxe Hennessy is always my preferred backpacking hammock, although my wife, Anna, likes the Speer better, because of the top entry. She still gets claustrophobia in it, especially in bear country.

Jeff has a greta site that has TONS of info on hammock camping including instructions on making your own hammock.

http://tothewoods.net/

I have instruction for making a DIY version of a Hennessy:

http://www.hammockforums.net/forum/showthread.php?t=670

You can go pretty light with the body fabric. A fellow BPLer has used some sort of superlight silk, I think in the .7-.9oz/yd2 range if I remember correctly. I think the fabric choice comes more into play when you get into the warmer months, when you have to balance a) breathability in hot weather with b) the ability of bugs to bite through. If you're planning on using a sleeping pad or underquilt, you don't have to worry about this too much.

The underquilt shouldn't need to take any of your weight. It's usually fit to hang from and rest against the bottom of a human-filled hammock, but not made to support the body. For the underquilt top & bottom, I think silk or a light nylon would be easier and less friction-y/bulky to pack than netting.

For another resource, check out Risk's webpage for info on DIY Speer-type models. I've done his $9 test hammock, which you can make in about 15 minutes. He also has some great info on whipping and knots. There's an active Yahoo hammocking group/mailing list, as well.

-Mark

Thanks everyone. I'm going to take the advice to build cheap and cheerful to heart... hammocking is a whole new world. It strikes me as less than simple in cooler climes. Great resources that I'll look at closely.
The impetus for this is the relative(imagined?) ease of finding campsites in the northeastern mountains. I struggle a little with the weight gain that seems to be part and parcel, and the greater complexity of staying warm.