Hi tsteever, Welcome. You came to the right place, I am sure there are folks who can help. NOT sure how many use macs, and the folks using Rumba are not many but I think it will get figured out for you. I have ramps and linux so not much help, but for one thing the paper thickness is the way to go for leveling. I use the home or z home in pronterface, and have not really used the LCD for that, you could see if that gives you anything different. As for your part, I have no idea what an afinia looks like, I will look it up, but I am sure it took tuning to get to the way it is printing now. I am confident we will help you figure this out, and you will get TONS of support here. These guys rock!