How do I select the right diamond carat weight for my grinding wheel?

Carat weight selection primarily depends on the wheel diameter and width. As a general rule:
Wheels 200mm: 0.25 to 0.33 ct.
Wheels 300mm – 500mm: 0.50 to 0.75 ct.
Wheels 600mm: 1.0 ct or higher .
Using an undersized diamond causes rapid overheating and premature tool failure .