Brand new to this. I've made 5 hammocks, used all sorts of whipping, all trying to find the elusive flat lay. I have a 12' version I use try different whippings, shorten the length, and do all sorts of adjustments.
Here's what I've found. Lay in it a while (hours). Adjust the sag a little (usually I add more sag), lay in a while longer.
I received an ENO for a gift so I decided I would lay in one that I knew folks said was comfortable and find out what it was supposed to feel like. I have spent a lot of time (0 nights) but lots of hours hanging in the ENO Double nest 68"Wx9'-10" long, I think. Without adjusting a thing, all of a sudden, I wiggled and scooted the right way and got real close to flat and very comfortable. The sag was way more than I thought I needed, close to 40-45 degrees in the support lines.
I was able to lay on my side comfortably and fell asleep for a little nap.
I don't ever think I have been dead flat, like laying on the floor, but now that I have found out how it's supposed to lay, I don't think dead flat is what I was looking for after all.
If you are like me, you are having more fun making them than sleeping in them.
Take a few naps.