NOTE: I finished this before I took any pictures, and took pics as I undid and repeated the process. So I will try to make sure that the pics are adequately explained. Any questions just ask!
N.B. It probably goes without saying, but whatever you do for one side, you're going to do for the other.
Step 1: Supplies
Paracord - about 25-30 feet of it
Pencil - to sketch out what you'd like the web to look like, where you want it to go, etc.
Allen wrench/screwdriver: I used these to remove the straps and side rails, but I realized you didn't need to after I finished.
Step 2: First Paracord Wrap
To secure the cord, I tied two double fisherman's knots on either side of the NVG mount. It looks kinda nice, and it's pretty taut around the helmet. Exactly as needed.
Step 3: Here Comes the Fun
Again, I took most of the pictures as I reversed the process, but wherever I got stuck I tried to take new pictures, so things should be reasonably clear.
First up, I started from the back once again, folding the cord in half to make sure both sides were even. Then I threaded the cord through the two rearmost bottom holes, and up through the accompanying holes above them wrapping the cord around the first wrap. Then I threaded the cord through the rearmost holes on top of the helmet, so that they crisscross inside the helmet. (Pic 1 and 2)
Pic 3: View from the front of the helmet
Then into the middle holes, cross over to the actual middle hole, then come out of the front two top holes. Confused yet? (Pic 4 and 5)
From there, out the top front holes (above the NVG mount), cross over into the holes once more, and back up and out of the top front holes. (Pic 6 and 7)
Step 4: More Fun
Pic 2: Crisscross the cord, thread it back into the top holes, and out the bottom holes
Pics 3, 4, and 5: Cross the cord over the middle hole, then wrap each over the opposite cord that is going into the middle hole (confusing, but check the pic)
Pic 6: In through the top holes (from the front) then out the bottom holes.
Pic 7: Weave through the next two holes, then wrap it around the back of the helmet.
Step 5: Even More Fun
For some reason I decided not to take pics at the next part, so I'll use an overall picture to show you where to go from here (Pic 4). Basically in the top hole, out the bottom one, back up to the middle, do a little wrap around there and angle it out to the opposite side.
Step 6: Almost There
This part is easiest to describe using the pictures, so refer to them. Basically you want to connect the cord coming from the top of the helmet, and bind it to the first wrap, as well as the part of the cord that wraps above the rails.
Step 7: Finishing (Finally!)
Now the cord should be riding toward the front of the helmet above the rails. Now you've gotta tie it up, and I used the double fisherman's knot again, just to keep things regular.
Once it's cinched up, you can trim the cord as short as you need or want it to be.
And that's pretty much it! Again, it's kind of confusing, but if you work it through, and do what works for you, it'll turn out great.
If you need any more info, let me know! I'll see if I can get a video going (that will probably be easier to understand).
Thanks for reading!