Best use of bonus drops?

Same # of shards on average regardless of if its 10*10 or 5*20.

The difference is in your "Range".

The smaller the energy the lower your chance of a drop but the higher your total Max could be.

So in the above, if the average is 3% you'll "average" 3 Shards for that 100 energy, but your ranges are 0-10 v/s 0-5.

The average is 3, but your 0-1-2 will be WAY more common in the 0-5 run to make up for the 0-10 having some high shard chances.