Machines are courtesy of my employer, they were kind enough to let me use the equipment on the weekends and during holidays. Just wait till you see the WaterJet cutter
As far as castings are concerned, I have seen worse, a LOT worse ( not from Stuart ) ! Hard spots, inclusions, porousness, and yes you are right, you always discover them on finishing cut !
Imperial is ok, been working with it for a long time, in Australia we use a mix of both, metric and imperial. But still, when I encounter 21/64 or something like that, I have to reach for the calculator.
I will have to buy some taps and dies, mostly BA's, the rest should be available at my factory.