Hello
It's me or even at maximum size and frequency the ore patches are minuscule?, what's even the point of having a size slider if even at max size the patches are so tiny?

Have you actually tried mining from them with electric mining drills? I was put off by the size as well until I actually mined them with drills. They spew out so much ore that burner drills fill up in a few seconds and a single electric drill can saturate the basic conveyor belts.

I'm currently trying to figure out how to drop the output. I suspect it's the yield that I need to change. But I need to first figure out what value equals the vanilla ores.

It doesn't really matter the density - a small ore patch have a limit output of how much ore / second you can extract from, in fact, even if it cost more resources in the short run, a larger, spread-out patch it's better because you can place more miners and thus getting an higher ore / second.

Also regardless of the consideration above, what's even the point of having a size slider if even at max size the patch it's still pretty much the same of a normal-small sized one? may as well just disable the size adjuster.