Diamond blades are way better than carborundum blades. You can get hundreds of feet of cutting from a diamond blade, the depth of cut doesn't change much, and the cutting is faster.
The carborundum (masonry) blades grind down quickly, you need a stack so you don't run out.
With either, a drizzle water system really improves matters. Otherwise you get blinding clouds of dust. Keep the material damp, soak the mortar joints before slicing them. Drill a relief hole where you change directions so the cut doesn't spider into a crack.
Wear really good eye protection. The dust settles on plastic lens of goggles by static charge, you desperately want to leave them off. Don't-- after getting a carborundum grit removed from my cornea, I learned my lesson- it was painful. A cheap glass diving mask is a good choice.