i am sure you will get feedback from more experienced weaver than I, but I love weaving with wool silk and wool cashmere blends on my rigid heddle loom. Personally, I do not have any particular problems with my selvedges using these blends as opposed to plain wool. On my Schacht Baby Wolf I am a huge fan of floating selvedges hung with weights off the back of the loom. This may be a “crutch” for me and as I gain experience I will not feel the need for them, but for now they help me a great deal in keeping the edges of my weaving even and straight. As far as your weaving being slow, that’s one of the things I like about weaving, but that’s just me.