it depends what conditoin is blade before i start to sharpen blade
my lowest grit is 1000
highest is
Escher has been for a long time but i know find out NAKAYAMA DOES same or better job
in the middle of it could be
used norton 4/8k i use alot because it is cheaper
and many more natural 4-7k stones
Belgians you named it
again middle depends on blade conditon ,material and etc
if you check that picture i think they even not come out 8k.
he uses some lapping paper which i am not familiar with but i know how edge look like after final finish with natural hones.
hope this helps.