I measured and marked the cutout for the notch to my satisfaction. It's 20mm wide, which provides room to put a 13mm socket on the oil fitting. Note my aforementioned patent-pending seal for the opening, fabricated from thick, extra-sticky Gorilla tape. How sticky? It took a lot of pulling to peel the prototype off. It seals the opening tighter than a bull's rear end at fly time (one of my dad's expressions, approximately). Not a chance of aluminum particles from grinding getting past the seal, but as belt and suspenders I stuffed a paper towel in the opening before sealing it. I'm ready to grind the notch. Unfortunately, that will have to wait until tomorrow due to a previous commitment.
