I spent inordinate amounts of time and research this past winter asking the same questions as you.
I ended up with Sta-Set 3/8" DB in dark blue. I find it to hand well, lay nice and has very little stretch. I calculated that at 85 degrees out, on a DDW run, my boom-to-center transom measurement X 4 was near to 70 feet. I had the rigger add 5 feet to have enuff. I am happy to report that I did a DW run wing-on-wing on Monday and *did* need most all of that length!
Trevor at Harney Rigging did me a solid deal on all my lines. Excellent work, great commo and super fast service; plus great pricing