huh. i was planning do a mob farm above an ocean at at 170+ that way there are no mobs in a radius of 128 since the oceans go down to about 40 and possibly even deeper. plus then there's no need for quarrying.
i guess that's an impressive big hole though
While that is a much better design, I don't have any oceans and the reason I built this in this location was so that it'd be running whenever I do anything in Capital. While there is some unlit caves, I got most of them through a lot of tunneling I have done. The lack of efficiency should be compensated by not having to sit there and afk for it to work.