Hi James. I always shoot the hood laying flat. The clear goes on so much better, and if you are planning on cut and buffing, having a bit more dust in it from laying flat is not an issue. Interesting that my home garage booth was amazingly clean and I had almost no pollution in the paint...lucky. I first mask off the top of the hood as in the pic you posted. The mask line is not noticeable at all along the edge of the bottom side of the hood. When painting the bottom, I have the hinges open as in the pic. Once the bottom is dry (I let it sit 3 days), I tape off the bottom and paint the top flat as well. I tape off the hinges that were painted open and then close them to do them closed. That gets both sides.
For the windshield, I paint it off the truck as well. and hang it. On this one I am mounting a full hardtop so the windshield will not be coming down to the hood. I focused on making sure the hinge was painted good in the closed position which is what will show. Of course the entire hinge was epoxied and primed both open and closed so it is well protected. The hinge, as you know, is hard to move on the windshield when off the truck. So I pretty much got it as closed as I could get before hanging it and painted it that way. Came out super nice. If I were painting a Bronco where the windshield might be lowered on occasion, I would buy the SS hinge and not paint it at all.
The tiny little white you see in the hinge seams is actually buffing compound that I have now cleaned out (after this pic was taken).