I'm not a dirt a king, more of a dirt squire.............or maybe just a dirty hippie.
"Can I use Dolomite, Murite of Potassium, and clay with MGOCPM?"
From what I've read about it, not only can you, but you are supposed to. The clay helps hold together the mts and provides iron. The dolomite is said to be optional depending on your water hardness. Potash, what could it hurt?
I made some MTS and used pottery clay powder, iron oxide, greensand, a little organic fertilizer and a sprinkle of peat on bottom glass. It's been about a month but the growth is amazing.
Just don't make it too deep or you'll get anaerobic conditions
As far as DSM, never tried it, but the process of microbes "mineralizing" the soil occurs whether the soil is spread thin on a tarp or submerged as aquarium substrate, it just occurs at a different rate.
True, the pic looks a little sandy, but after you mix in the other ingredients it will be a nutrient packed plant growing substrate.