Sorry that I still give a ***, but here we go:

Everyone has figured out any resource gathering fit (harvester or miner) is best fit with full indy tunings in the head, and all accum mitigation possible to support this.

Given this is the current balance, small modules are being used over mediums categorically.  Mediums have no use!  Their base accum is high, and all you get is a faster cycle time (also increases accum drain/s).

So if the tuning balance is here to stay, I suggest a few considerations:

Give Mediums (and their increasing tech levels) a mining amount bonus,
OR reduce their accum cost (and maybe look at their power/cpu as the fitting limiter instead)
AND/OR balance cycle times (ex: make cycle times the same, but only add mining amount bonus w/ tech and size).

Either way, there is no upside to using mediums.  Overall yield is so high with stacked tunings, it well outweighs the cycle time reduction.

Thanks,
-null