I love madder root!
The only bummer is that depending on the amount you use, it will color a wash rag - which you can rinse out as you use it.
I use madder in two of my bars cause I love the color and I just put out the disclaimer.
I add my ground madder at trace in two ways.
First, to color the entire batch a deep color - I take a pitcher full of soap out of the pot and whisk in the madder (1.25 oz) and then add it back to the pot
OR I whisk in the pitcher (a heaping TBL) to use it for a swirl.
I haven't experimented with infusing or adding to lye.
This is for a batch with 5.375 lbs of oils.
I've also used a lesser amount for a pink swirl that is pretty nice and seems to stay well.
I haven't figured out how to load pics here, but if you go to this link you'll see a picture of my madder root soap from the Nostalgia Swap. Scroll down to Eclore Soap