Never heard of the second hone and the grit of a Swaty can only be guessed at. From the info I have the finest grit size available & used in those days was a grade called 1200F. To use an analogy... it was put thru a sieve that allowed all grains 1200 grit and finer to pass thru. From the size distribution graphs I have seen this corresponds to about 6000-8000 grit by todays standards. But... as Hi_bud_gl mentioned, there were additional processes performed in the making of some barber hones that would reduce that grain size. If those processes were used to make the Swaty I do not know.

Hope this helps,