I recently attended a Hatfield forest wild camp at the end of August that the National Trust organises in conjunction with JP and Pablo (Woodlife Trails) they did various demos and tracking walks the idea of the wild camp is that the attendees to do whatever they wanted (within reason) since they were in a 1000 year old former hunting forest.
As I was on my own with no family what better time to try out a new DD tarp (and whoopee slings) so I made my way to a suitable spot, got set up, then took it down and started again. I decided that the rain that was due necessitated me re-aligning the tarp and hammock to take advantage of more leafy protection...So glad I did.
Apparently the reason most tarps are 3m x 3m is that the material used to make them is 1.5m wide and I'm sure I'm not the only one who has wished they were a little longer as they finely adjust the position of their hammock! I'd considered getting a bespoke one made but the DD Tarp M sizing is more or less what my proposed bespoke one would have been, in length at least.
The dimensions are 3.5m x 2.4m which is a little more like the Aussie tarp that Mr Mears favours but that said it's about 3 times the cost and smaller. As you can see you lose 0.6m of width compared to a standard 3m x 3m but I still found the area very workable as a living space, especially as I elevated one side slightly with a couple of lengths of hazel.
I modified the three central ridge loops by tying an overhand in them because they are much larger than the two on the end and once you've got a couple of prussic tensioners in place the ridge line takes on a concave appearance.
As for the whoopee sling system...I'd always felt that they looked faffy but decided to take the plunge and try them out. I took Adrian Rose's advice and put a split ring on the loop as it could easily disappear into the main body of the loop if you pulled to much. Consequently I'm converted to the point where I wonder if DD Hammocks should sell their hammock with the choice of either whoopies or webbing.
Regarding the larger central ridge loops Nick from DD Hammocks answered the technical reason for the loop size which I sent via email which you may be interested in reading:
Regarding the loop sizes you're not really missing a technical point. They are bigger because once the tarp is pegged out (in the middle), there is often more pressure on the middle points (if they are pegged downwards, straight to the ground) and so being a little longer prevents excess stress on them (as the middle of the tarp is likely to be slightly lower than the ends of the tarp). The middle loops are still very strong but not as super strong as the side attachment points are due to the placement on the tarp and use of re-inforcement patches at the sides (that makes it sound like the middle ones are weak but they certainly aren't and we do not hear of any weaknesses/ issues with them at all). If the middle sides of the tarp are not pegged at a steep angle to the ground the loops can sit a little loose.
The middle loops on all of our tarps are like this and as you mention its possible to tie a knot to make them shorter if required.
That makes sense, I have used the tarp since and believe it benefits from two central guy lines (making six in total) but I didn't pull them very tight, rather I added them to just help with the tension due to it being a little longer than the 3m x 3m workhorse which I use four guy lines on.
This is the tarp on a later cub camp with the knotted ridge loops...and gently tensioned middle guys!
The Scout Association shop has now started stocking DD Hammocks' stuff (which I'm rather chuffed to have had a hand in). You can read Pablo's blog entry about this and other Woodlife Trails activities on the official website, and see the discussion about this weekend (along with a link to my Facebook photo gallery of it) here.