Great setup! I used Dutchware's Halfwit this past spring/summer and loved it. It's rarely buggy (surprising) on the southern part of the AT, so I was able to cut a few ounces but still have plenty of coverage if needed.
Dutchware Halfwit with whoopee sling and tree straps*
Hammock Gear Cuben-Fiber Hex fly (in camo of course!)
Hammock Gear Burrow 50
I do have a JRB under-quilt, but it won't see the pack until temps dip below 50 at night.
The Burrow 50 was perfect to really cut weight and still provide enough insulation for summer trips. I think the coldest night was in the upper 50's on one shorter trip, but I was perfectly comfortable. Instead of the under quilt, I use a section of Z-Rest (folding) sleeping pad in my hammock which works enough from butt to shoulders.
*I tried some of Dutch's Kevlar Tree Hugger straps, again, thinking I could cut some grams...big mistake. These are really thin straps, so thin I actually kept a backup, regular nylon webbing strap with my hammock (so much for saving weight!). I use Dutchware's titanium Dutch Clips for the tree straps and if you're not extremely careful, you can easily punch a hole and start a tear in those Kevlar straps. Long story short, I had an embarrassing tree strap failure, with a no-notice break. My only caution is if you use those Kevlar tree straps, be extremely careful when setting them up and if you get any sign of a tear, switch them out. I really don't recommend these straps; this is one time, gram-counting isn't the best option.
ROCK6