Hi mate ^^
Maybe it's me but... don't you find your chucks very wide? I'm acostumated to thin sticks, I think they are pretty much faster and they hurt a bit less when you fail and hit yourself.
About the cord, I'd use a rope for climbing, it's more safe.
If they slip too much, you can tape them, but in my opinion they will seem bad looking. You could try by sanding them into a non rounded form (octogonal, maybe), that should give you some grip.