What I mean is that incident metering is the equivalent of placing a mid tone as a mid tone. You don't meter for any tone. You meter the intensity of light that exists, and use that to place a mid tone as a mid tone, high tones as high tones, and low tones as low tones. Shooting this way, you go into it knowing how certain luminance ranges are rendered with your particular film at certain exposures and developments, and can thus use these exposure and development alterations to change contrast.
I can recall no more than a handful of landscape pix I have ever shot in which the light that is illuminating that which is within the composition cannot be measured with an incident meter, or barring being able to put the meter into the same light that is illuminating the subject, an educated guess. For instance, say you are in average shade, the subject is in the sun, and you can't find a sunbeam to measure. (As I said, a very rare occasion IME.) Take the shade reading and stop down four stops. If you are in dark shade, five or six. Light shade, two or three.
Since I switched to incident metering as my primary method, I also cannot recall many landscape situations in which the use of a spot meter was anything but a helpful addition to my incident reading, letting me know exactly how much to alter exposure and development as opposed to me just making an educated guess as to how much to alter them. In other words, no spot readings I have taken have ever drastically changed the exposure I would have used anyhow if I had just used my incident meter and an eye for luminance range.
If you really love your F5's meter that much, it is worth it to bring it with you. (Then you have a 35mm as well, which is very handy in almost every situation in my book.) However, I can guarantee you that an incident meter or a spot meter (assuming they are used correctly) will both give consistently "more ideal" exposures than any directly-read in-camera reflected meter, and this will always be the case. A meter that reads the composition and tells you how to expose to average all tones to a half stop below middle gray (which is what all in-camera reflected meters do) will always be a compromise. That this is the case is pretty much the entire reason for using hand held meters even with today's supposedly "intelligent" in-camera meters.
Where I find spot meters are extremely useful is in pictures in which I want the tones in the print to be vastly different than they are in reality, or when there is an extremely high contrast composition.
There is no reason not to use a spot meter alone, if that gets you exactly what you want all the time. I am just trying to downplay the idea that they are the be all and end all of [landscape] light meters. They are not magic, and IME will not change your results for the better all that much in most situations. They are just tools, and are only as good as the person behind them.
I got mine over the counter brand new at Calumet a few years back, after finally giving up on the battery issue with my 1/21 that I had had for some time. It was not listed on the Website. KEH has them at times. They show up here on A.P.U.G. as well, usually for under $300.
I know that locating them is very hard. However, the last time I said this here, several people said, "No it isn't", and named some places that carry them. Were Badger Graphics or the View Camera Store perhaps mentioned? I don't remember.
The only place I have ever seen them priced over $500 brand new was direct from Pentax.
There is also absolutely nothing wrong with the older model Spotmeter Vs either. The ones you probably want to avoid are the 1/21 models, as they take two batteries, one of which is no longer made.
IMHO, if you are set that you are going to spend so much on a used one, I'd just spend a bit more and get a brand new multi-whiz-bang meter that does flash, incident ambient, wide-field reflected, and spot. They are around $500 to $600, and until you break it, you'll never need another light meter.