@XFmax you can't make coke from charcoal, but you can use coke or charcoal in blast furnace (just not dirty bituminous coal). Also coke ovens work on wood, but give smaller creosote oil production (however TFcraft has the best way for charcoal production, I would love to see some balanced automation in it). You can get magma cream about the same time you get glowstone for pstone, so I would be careful with this RM overflowing thing. For nether you just need 3 iron/tin and lava pool.
Edit: And magma cream is a lot faster to get, than slimeball. Cubes spawn quite often in the nether (definitely easier to spot, than endermen in the overworld).