It doesn't matter if you have several hives of small amount or a single hive with a big amount, only total amount counts.
Cause when the wallet try to find a hive block, your swarm of all hives works as a single unit.

But, during hive mining I experienced that too small hives don't give good result. Try to make your hive size of at least 100 dwarves.

Okay, I will write soon.