Ok, so confusion aside (and I'm definately getting a little more confused here, not less) there are a couple of points here I'd like to clarify.

With a super takumar lens mounted, and the DOF/meter switch in the 'down' position (ie, 'off' from the point of view of one of the older spotmatics) the meter on my F responds, and indicates what seems to be a roughly correct exposure. From what I'm reading above, this exposure reading should be disregarded, that the SP F will meter correctly with super takumar lenses ONLY if the metering switch is slid up. That this reading (When I switch up the meter) is about 2 stops too slow is certainly an issue, but needs to be considered in isolation. I've got 1.5v silver oxide cells in it, roughly 80% of the internet seems to think this is fine because of the SP f's bridge circuit, and there's a vocal minority that claim that this view is mistaken.

I actually have an SMC 28mm that I can grab tomorrow so I can check the flipside of the coin, open aperture metering with the right lens.

I've -also- discovered to my annoyance that one speed is flaky, or rather one EV, ie 1/250 at 400iso or 1/60 at 100iso. This is the same as another of my older spotmatics, and I bet it's the same cause as well. Dunno if you've ever dis assembled a spotmatic, but the shutter speed selecter linkage to the metering circuit is two thin copper discs with a small contact between them. Both cameras sat around for years before I got them, I'd say there's a tiny spot of corrosion in the spot that little contact was sitting all those years or something. Hopefully lots of actioning it might clear it up a bit.