Jason, it isn't actually a spotmeter per se. As I understand it, it meters from the same fixed area of the viewfinder--in mine, the meter hot spot seems to be about the same size as the rangefinder patch, and sits just below it, with perhaps some overlap. When you're shooting the wider lenses, this spot is a small amount of the total area of the final image; with the longer lenses, it is a smaller portion of the image and is more like center weighted average.
I've had my Mam7 only about 2 months and I'm still figuring out its quirks. I love it, though. Strangely I've had an easier time using it with color negative film than with B&W, possibly because with B&W I'm in Zone mode and tend to overthink things. The lenses are the only ones I've yet used to rival, or exceed, those on my Contax 645. I have the 80, 150, and a 50 on the way. I think you'll enjoy it immensely.
Mike Sebastian