Yes, clays can affect the feel of your soap. One of the most tangible effects that I find is the really nice 'slip' that clays bring to my lather, which is excellent for shaving soaps. I like using kaolin clay in my shaving soap at about 1 to 1.5 tsp ppo.
Of course, color is affected as well depending on the color of the clay (I love rose clay for the nice pink color it gives my soap, for example), and it can also cause soap to feel drying depending on what clay you use and how much you use of it (some clays are more drying than others). I like to use kaolin clay and rose clay because they are on the mild side of the chart where causing dryness is concerned, and although French green clay is rated for more oily-type skin, I've used it @ 1 tsp ppo in some of my soaps without it feeling too drying to me.
Will the superfat seem lower?
Depending on what type and how much you use, it can make it
feel like it's lower (although it isn't in reality). Since everyone's skin is different, though, you'll just need to experiment with how much and what type works for you. I would start out on the low end, like about 1 tsp ppo, and then go from there adding more or less according to how your skin likes it. If it helps, the 1 to 1.5 tsp of clay that I use in my soaps is enough to lend a nice slip without drying me out at all, and it hasn't put a dent in my lather where bubblage is concerned either.
HTH!
IrishLass
