Something I was asked to try by a Tenkara friend. He told me what he looks for, so a few trial and errors, I came up with one that others liked as well.
There is a big taper to them. Example a 10 foot leader will 26 to 6 with a taper of 26 - 24 - 22 - 20 and so on to 6. They roll over beautifully. I got the idea from LaFontaines Floss idea. Float the fly on top the water.
I do use lighter thread as well. Probably equals out to a 6X. Obviously, the advantage is with dries, but nymphs are no problem.