That's interesting, I would have rather expected that the value 'irq_period' had to be changed instead of the 'start_delay', but it seems to be working indeed!

Is this value 2000 also ok for the other Constellations in this driver (they have a value of 17200 instead of 10200), or should it be set to any other value?
I'm asking because maybe I'll add such a frequency menu to all of these machines.