Pinion angle....with pics

Maybe if you could find it in your heart to tell us what you're doing with the car it would make the ultimate answer more accurate. Street car? -3 degrees is ok, as Rob said. Hot street/drag or drag only? Then you want what the MP manual says. 5-7 degrees. Technically with SS springs, that's where it "should" be anyway, 5-7 degrees. But again, if only a street car, then what you have is fine.

The car's position doesn't amount to a hill of beans when you measure. As long as you have the weight on the tires. You could theoretically flip the car upside down and take the measurements, as long as the the wheels and suspension were still in the "loaded" position. It sounds like you get that part, though. I like how you leveled it up to make the math easier. That's how I always do it, too.