"That said I will state that the new D800e body is a game changer. "
That may well be, but DSLRs are not the only types of cameras out there and are sometimes not the most appropriate choices -- ANY DSLRs. For example, for many types of photography, a rangefinder or a view camera is a far better choice.
"BTY for those of you having trouble with focusing in low light, you can use the "live vew" and associated zoom in to get round it."
Actually, I think a film camera would be a better choice than any DSLR in low light, and (because of the way it focuses) a rangefinder would be the best choice of film cameras. They are much easier to focus, with great precision, in low light. A film camera will have no noise at all, which is often a problem with DSLRs, you can take exposures lasting hours with no problem, and if you have an ultra high resolution film, then grain is not a problem either and the level of detail will be incredible. You do have to have the whole system though, including an enlarger with a good lens and a darkroom to get the full benefit of it.
DSLR are what most hobbiest are using. Just saying. I have been extremely happy with the D800e. But I wish I did have the 4x5 to lug around. It would be better suited for a lot of what I do. I might also force me to be more aware of what I am doing as apposed to clicking off several shots bracketing just to be sure. The DSLR is just easier. Anything that forces me to think about exposure, composition, highlights/shodows, texture and form is a good thing. A 4x5 would do just that. A single fixed lens will too.
I use to shoot lightning as a younger man using the Olympus OM series cameras. Unlike the modern Nikkor lenses there was a stop at infinity. Not so with the newer Nikkor AF lenses.
I used Kodachrome 64 or Ektachrome 100. Both would suffer reciprocity failures to a degree with longer exposures. It was expected. The longer exposures with sensors does lead to noise but many of the modern DLSR have a noise reduction for high ISO and long exposures. The D800 does not seem to be as noisey as the D700. Still I am satisified with the results of both. No so much with the D300.
There is one aspect of DSLR and lightning photography is that you can take many many shots, many of which are simply blank as no lightning happned while the shutter was open. On good nights I can rip off 300 to 600 shots. I could never do that with film.
Uh... do you know what exactly reciprocity failure is? Every film ever made has it. It's a point of diminishing returns that starts around ten seconds into an exposure. It doesn't mean you can't get the shot, it just means that your 10 second shot is going to take 10.25 seconds, a 30 second shot is going to take an extra 2 seconds and so on. Nothing actually fails though and you can take exposures that literally last a year or more if you want to. What it means, in practical terms is that you will need to look at the reciprocity table for the film you are using and do some simple addition.
With film, you simply leave the shutter open until the lightning flashes.
As for the Mamiya, get either some "stove paint" at the hardware store, or Krylon Ultraflat black spray paint. If you get the Krylon, spray some into a can and brush it on where the flocking is missing, Stove paint is the kind of paint that they used to use to paint old-fashioned pot-bellied wood stoves with. Both are extremely flat, stick really tight, and work very well for flocking a camera.
As for the magenta tint: You were getting that with Kodachrome? I'm having trouble imaging that, since it was one of the most reliably accurate films ever made. I'd be more apt to attribute that to a poor coating on your lens than to the film. You didn't get one of those crappy lenses with the red lens coating back then did you?