Pretty easy really.
Made a 2 layer per the sticky instructions above.
The inner most layer is not permanent and will be removable.
Also going to make a M50 2.5 XP outer layer to clip on the suspension.
Made it with 3" baffles at the ends, and that seems to seal it up pretty nicely.
I have stretch cord going through those to a center grommet and a cord lock.
Hemmed the entire thing with grossgrain with a single grommet in each corner, so that was easy, but if I did it again I think I would use silnylon so it would slide around easier, easier to adjust. PIA to sew though.
Took about 4 hours to make.
1.1 oz digital camo outer shell.
42" wide x 60" long - 12.2 oz