I just dug out a 23x23x23 cube for the lava lake a lack of cobble is not a concern for me at the moment. Right now it's going into a clay generator. By the time I run through that I expect I can get a parallelized cobblestone generator built. So far belts, andesite funnels, and tech reborn storage buffers are serving well enough for item transport. The latter can filter items and transport them in any direction stacks at a time, and are just made of wood and sugarcane.