Not sure what fiber to use for different types of felting ? I am constantly frustrated by my confusion of different names for different sheep and what will work for what . The following link is a good reference point for us none 4H type who don't know our sheep from a goat in the ground .
So far, I prefer merino for wet feltng, smallest micron count possible for nuno...18-21 . I love alpaca but have problems with it shedding in wet felting and takes much longer to needle felt . The medium fibers have worked best for me for needle felting...Romney, colonial and Shetland have all felted very fast under the needle but I still like merino on the outside for it's softness . I still have many fibers to try but I think the micron count is a pretty good indicator of what fiber to use for which technique . Smaller for wet felting and larger for needle felting is a simple rule of thumb but can be broken like all rules .