Hope following helps. The make, model and size of cooktop or range will determine size and power of hood. The manufacturer should provide guidelines for hood spec but the general rules I follow for home professional style heavy duty stovetops or ranges are the following:
1) the hood is as wide as stovetop
2) hgt above cooktop is between 30-36"
3) depth is from 20-24"
but all dimensions vary depending on requirements of cooktop manufacturer, and design desired.
3) overall hgt and of hood depends on may factors: manufacturers specs, ceiling hgt, whether it vents out of ceiling or through wall, whether it is exposed or hidden in cabinets, whether it'a custom design, etc…
4) down draft is also an option if it works for you house but generally not as effective.