I have F-1, F-2, and some mixed, where the sire and dam were different generations removed. On that note, the most accurate results to me would seem to be those achieved with eggs from fresh-caught imported gravid females, not yet subjected to the whims of captive husbandry.
I also have not attempted to hatch pardalis eggs without a diapause for many years. It is my belief that a diapause is the natural process, by which this animal has viability in the wild, while all the other things that happen in captivity can easily produce different, and less predictable, results. A proper diapause will give consistent results on hatch times. Remembering back to my non-diapause days, I have had separate clutches produced by sibling pardalis (not siblings bred to each other, but sibling males bred to sibling females of a different bloodline), kept at a uniform temperature throughout development, where the hatch rates between clutches could vary by as much as three months. I have had eggs with no apparent diapause hatch in 7 months, while others hatched in 13, leaving me to wonder if there wasn't still a subtle triggering mechanism, less obvious than a more substantial diapause. My point would be that to not have a diapause is to introduce factors that will change the incubation period regardless of Locale. As with any experiment, when one eliminates one or more controls, in this case a diapause, the results are tainted and inconclusive.