Shock cords for tent lines
For several years I've been using shock cords on my tent lines. They are sold in fishing stores as snubbers, and they come in various sizes. For fishing they serve to absorb some shock when a really big fish hits a line, so the line doesn't snap. In tents, they also serve to absorb some impact, such as when a tent is in a severe wind gust. With the snubbers, my tent has survived micro bursts, wind storms, and being knocked around by wind for hours.
I have them on the tent lines that hold up the front and rear poles of my Tarptent Squall 2, and on the 2 side guys for that tent. I would get the large size and the thickest size they have. They are made of surgical tubing, and have metal loops on the end that make it easy to connect them to your tent lines.