I want to use a rope and prussic knot for safety while ascending and descending my tree stands. I looked at Lowes today and they have 3/8" x 75' rope for $14, that's only 18 cents a foot and its camo too. It holds 240 some pounds. I've read that the prussic is to be 2 mm smaller than the rope but the next size down, I think it is 1/4 or 3/16, is rated below 200 lbs. What size rope should I use for the prussic? And should I spend more money and go toa rock climbing store to get real climbing ropes for 60 or 70 cents a foot?