neuroscience - Are large cell bodies of neurons harder to depolarize than small cell bodies of neurons?

In order for the axon to initiate an action potential, we know that the axon initial segment must be brought to threshold. So my question is as follows:

Say we have the minimum charge input, "X", necessary to depolarize the axon initial segment of Neuron 1.

Now, we have Neuron 2, which has a larger soma. Will this same input X be sufficient to depolarize the axon initial segment of Neuron 2?

I am trying to explore how physical concepts like capacitance manifest in biological systems. Neuron 1's soma (approximated as a sphere) presumably has a lower capacitance than Neuron 2's soma (approximated as a sphere), due to the difference in cross sectional area of the somas. Therefore, I would assume that Neuron 2's axon initial segment requires greater input to depolarize than Neuron 1's axon initial segment.

Is this simplistic idealization of somas actually observed in experiments?