I'm also on board with Warren & I also use 4lb or 6lb mono (good ol' Clear Blue Stren) as tippet off a furled leader. I occasionally will use 6x or 7x tippet off my furled leader when very small flies dictate a smaller diameter leader.
BTW, if you've fished with Warren (as I have) & OUTFISHED him, you should brag about it! He knows what he's doing & I often pick his brain for information.

Mike