This is a pantin,
http://www.gonzoguanogear.com/images/pantin.jpg
With your bridge your suppose to keep it within arms reach so when you pull down you can easily advance the knot.Also so youcan get an easy grasp on it to descend.Imo the tautline works better than a blakes with a micro pulley but then again i prefer tautline to blakes.Use what your comfortable with and what you can tie quickly and get it right every time.