Instead of using a sheetbend or any other knot to directly attach a line to one's tarp grommet/pullout, I have found it far less hassle to simply tie a small loop in the tarp end of the line using a simple overhand loop or bowline. Just like how you would attach a yo-yo to your finger, one can then simply thread the loop through the pullout and run the rest of the line through the loop (kind of a girth hitch). Knots will not be stuck on your tarp, ever, and switching lengths of line among various grommets/pullouts takes seconds. Bigger loops can be better for speed here and can double as short peg loops like what RJ puts on the corners.
One other insight: My one small bungee loop I sometimes bring for my larger tarp is used on a mid-panel guy, and is dual-purposed as an easy hairband-style closure for my pack liner bag.
Definitely agree with the simple cord management technique of a knotted loop. I have tried and have seen others try to make neat little bundles of cord, which takes a long time and doesn't always keep in a stuff sack.
My next step is color-coding cord by length.