I'd say it would be pretty much impossible to put hard numbers against these nowadays, though we can of course generalise.

: How many 1158 do we know with the black date ?

The white on black date wheel is only ever shown on CHNs, and I've only ever seen it on this model, so we can make a reasonable assumption that it is restricted to CHNs only - Ss and CHs are always shown with the "traditional" black on white date wheel.

Once we do that, we can look at CHNs in the catalogues. First shown in 1970, the CHN makes an appearance with the white on black date wheel and continues to do so until the 1977 catalogue. It remains on sale for a couple of years at that point. I doubt annual production of 1158s was particularly smooth and certainly later on, I expect there were more or less made to demand so production may have been tailing off by the time the date wheel changed.

Certainly, given the black wheel ran from 1970 to 1976 and the white only 1977 and 1978, maybe a year longer if a customer asked very nicely, it's probable that the majority have black date wheels.

: The pulso seems extremely rare

Very definitely. Heuer were proud of the pulsometer invention, but it's not something that would have been useful for, or perhaps appealed to, their customers. Certainly not as much as the Tachy version, with its links to glamorous motor racing rather than the more prosaic taking of pulses! Perhaps nowadays it would be a case of you get what you're given, but Heuer made the choice available to the customer... and from what I've seen, those customers stayed away from pulsometers in droves. Which makes them all the rarer and more desirable today. I can't see any watch dealer taking a pulse watch on spec and expecting to sell it, I reckon these were made to special order.

While we're on the subject of rare first generation Carreras, the first execution Tachy on a black dial is another rare bird. I've long lost count of how many red-scaled silver dialled Tachys I've seen, but black Tachys I can count on the fingers of one hand. Never seen a Deci or Pulse black dialled first execution watch; I'm doubtful they exist but would love to see one if they do.

how many panda dials have we seen,

A fair few. Some have been Carrera 30s, and I find that a less desirable movement (the Valjoux 7730) than the venerable Valjoux 92 in the Carrera 45, regardless of whether the dials contrast or not. With panda dials, it pays to look closely - I'm not convinced that all of them are as they should be, or as they originally were.

There are quite a few uncommon Carreras dotted around the range. 73655 S, 110.255, 110.571 in addition to those above are some examples of watches that are harder to find than their siblings. Yachting markings 1153 in a silver dial, rather than blue? I've seen a grand total of precisely one.