Do they work OK at 1/90th sec and F8 also?
Joking aside, I know that auto-thyristor mode is popular, but really it should not be a more favoured automatic choice over P-TTL with a modern camera and flash. There's more work involved as you have to set the aperture and ISO manually onto the flash, and of course control the camera manually.
The older Pentax AF540-FGZ offers auto mode also, (using its built-in light sensor like those Nikons), The problem with using P-TTL sometimes is that its often combined with auto exposure modes and auto ISO on the camera, and this can take control away from the user. What sort of issues are you having with P-TTL, perhaps there is a solution? Ideally P-TTL is the least amount of work, because you can work in ,say, Av mode, fix your ISO and aperture and control both the ambient and flash exposures with compensation settings on the camera (for ambient) and flash (for flash).
Controlling flash exposure with an Auto-Thyristor flash can be quite a mental and physical juggling act.