If you start decomposing minds into their computational components, you find many orders of magnitude differences in the numbers of similar components. E.g. both a honeybee and a human may have visual experience, but the latter will have on the order of 10,000 times as many photoreceptors, with even larger disparities in the number of neurons and computations for subsequent processing. If each edge detection or color discrimination (or higher level processing) additively contributes some visual experience, then you have immense differences in the total contributions.
Likewise, for reinforcement learning consequences of pain or pleasure rewards: larger brains will have orders of magnitude more neurons, synapses, associations, and dispositions to be updated in response to reward. Many thousands of subnetworks could be carved out with complexity or particular capabilities greater than those of the honeybee.
On the other side, trivially tiny computer programs we can make today could make for minimal instantiations of available theories of consciousness, with quantitative differences between the minimal examples and typical examples. See also this discussion. A global workspace may broadcast to thousands of processes or billions.
We can also consider minds much larger than humans, e.g. imagine a network of humans linked by neural interfaces, exchanging memories, sensory input, and directions to action. As we increased the bandwidth of these connections and the degree of behavioral integration, eventually you might have a system that one could consider a single organism, but with vastly greater numbers of perceptions, actions, and cognitive processes than a single human. If we started with 1 billion humans who gradually joined their minds together in such a network, should we say that near the end of the process their total amount of experience or moral weight is reduced to that of 1-10 humans? I'd guess the collective mind would be at least on the same order of consciousness and impartial moral weight as the separated minds, and so there could be giant minds with vastly greater than human quantities of experience.
The usual discussions on this topic seem to assume that connecting and integrating many mental processes almost certainly destroys almost all of their consciousness and value, which seems questionable both for the view itself and for the extreme weight put on it. With a fair amount of credence on the view that the value is not almost all destroyed, the expected value of big minds is enormously greater than that of small minds.