The "magic number" for shaving soap is 50% or more stearic plus palmitic acid. Less than that and the lather will collapse too fast and the soap will not usually be slick enough for shaving, especially face shaving (legs are somewhat more tolerant of less slick lather).
Consider adding some stearic acid or soy wax to boost the stearic/palmitic acids in the soap. You will have to hot process if you add much stearic acid, it reacts to lye instantly.
I would also suggest using either castor oil or coconut oil, but not both, and I have reduced the coconut oil content of my shaving soap from 20% to 10%, and it seems to work better.
Make as small a batch as you can (preferable 250 gr or so) and test before making a large amount of any recipe, shaving soap lasts forever, you want a good one if you are going to have it around for years.