I use an Oware 10’x10’ flat tarp with a customized extra guy loop located in the center of the ridgeline. Even though it may be a little bigger than some would use, I find it extremely versatile, roomy and little worry of any splashing.
The 10x10 tarp has 5 guy loops on each side, and I usually only tie down 2 sides. I have precut 10 pieces of Aircore 2 to 22 inches and tie a loop at each end, leaving 18 inches end-to-end. From here you can change your length from a girth hitched 18 inches to 9 inches by doubling the line and passing it through the guy loop before staking. You can double the line again and make it a 4.5 inch guy line. Lower than 4.5 inches, you might as well anchor it to the ground. I then have four 4 foot sections with loops at each end so they can be girth hitched as needed for extra length when making an A-Frame. I do need to carry 12 stakes in case I use all tie downs with an A-Frame.
I do not keep my guy lines attached to the tarp. Girth hitching is easy to do and you might not need to tie down all points. I keep each precut piece coiled and use only as needed. When breaking camp, I re-coil each guy line used.
On occasions I have used the “Bombproof” shelter as shown in the book “Lighten up” by Don Ladigin. This is a variation of the ‘Flying Diamond’ using my 50 foot paracord to set up between 2 trees and is a very durable shelter.