I think the logic behind burning netherrack being hotter is that it's technically a higher Minecraft "tech" level than lava. In a normal Minecraft world you can find lava by digging deep enough or right on the surface in places but netherrack requires going to the nether, which itself requires lava for the portal. The fired crucible even works with an ordinary torch under it (heat level 1) but oh boy if you thought 4 heat seems slow... You can get water to flow back under the water wheel by making a channel on the ground around it and basically just giving it a new direction to flow in. Fun fact about alumin(i)um: The chemist to first isolate the element and therefore had discovery rights, decided to name it aluminum. The spelling aluminium was the result of a standards committee in England who insisted that all metallic elements follow the same naming convention, ending in -ium. So they forced the change in England but some other parts of the world did not follow suit.