".003 mono" You must be using 8X tippet. Depending on the material that would make a very thin furled leader but it would only have a break strength of 3.2 - 3.7 lbs. If you use the 10/8/6 taper.
I have used some 7X tippet material (0.004) that is rated at 3.1 lb. test so in theory the leader has 9.3 lb. break strength. That will be enough to handle most of my fishing but the suppleness of the material makes it hard to turn over large fly's or 2 fly set ups.