What I remember about the nordmark book - he throws away all his sand because a raccoon had walked across it ?!?! I could see this if the raccoon had 'sprayed it' - but no other reason. I do a lot of architectural restoration - specialising in terracotta and plaster - old time lime plaster, stucco. I see weak sand all the time -they used it to save money.To grind the marble is a lot of work - it will have to be 'screened' too. I could tell you the equipment you will need (an 'assay' grinder) The coarse white marble sand is used locally here for ashtray sand, for high class hotels, and as a part of swimming pool plaster -they like its bright white, which hangs in as the 'plaster' starts to wear away. Check with these two sources. The pool places also have dolomite sand I think. Thought I saw some exotic sands at artstuff.com too. Most people just use the dolomite sand - not quite as white, but widely available. Limestone/Dolomite = calcium carbonate plus impurities. Marble = calcium carbonate plus impurities.
I already told how to use fresco on a strong, rough surface - use concrete bonder and diamond mesh. This is no different than a pure lime plaster (no gypsum) and was done for centuries, all over the world, the difference is that we add pigment as the lime is curing. Michelangelo had a lot of problems when he first started because they cured to slow, and got moldy/efflorescence. He started to add 'pozzolans' and brick dust - which we get in North America as fly ash. In Pompeii and India- they had to protect the fresco surface from dust and grime, and often used waxes, or highly polished the painted surface with like a spoon. They did this in the middle east too - they use a glass bottle. The Israeli artist on this list uses that technique. Timing is everything.
There are SO MANY ways to do fresco - you have to find the way that works for you, where you are - that is the true history of fresco. Fall in love with painting fresco - not the IDEA of painting fresco - don't look for obstacles that are not really there. Are we really so vain that we must treat every piece we do as a 'heritage' piece that will be treasured, and therefore must be gauranteed to endure, into the next centuries?