I too have experimented with slurries with translucent and surgical black for years with good result from Coticules and Thüringen’s. I have also had good results from a natural Naugra progression on arks.

Using glass is just using the slurry by itself much like honing on the stone itself. Lap the glass with a Diamond plate to a flat frosted surface to hold the slurry better.
Using the slurry on a stone creates a synergistic effect from both grits.

Sometimes it works and sometimes not, as Ark slurry, does not break down like softer slurry. Much of the performance from slurry comes from many laps, breaking the slurry down further with each lap, as old time coticule & JNat users know well.

Very nice collection of stone by the way, nice translucent.