RE: Do NOT risk your life NEEDLESSLY...
I would suggest that if you are going to use a non-stretch type rope (static) as the tether rope, that you at least use a dynamic rope (stretchable) rope to connect your harness to the ascender. I believe I paid about .59 cents per foot for my rope 3/8 static (black). It's hard to find but some companies do make camo colored rock climbing rope.