I'm not getting it right somehow. I want the mega torch to burn out over a period of 96 MC days.
To this end I set:

I:MegaTorchBurnoutRate=2304000 (96 * 24000 ticks)

and I keep:

I:MegaTorchBurnoutValue=1

Is this correct? For some reason the torch keeps burning after the set time (I checked with different values obviously as a 96 MC day waiting-period is no fun)

You can check if the burnout is working by picking up the torch again. The tooltip will tell you if the torch is actually ticking down. There might be an issue with the "new" loading system, ill investigate.

You have your values mixed up. The I:MegaTorchBurnoutValue defines the "health" of a torch whereas the I:MegaTorchBurnoutRate defines how much of this "health" is removed per tick.

Change the Rate to 1 and the Value to 2304000.

I think i will change the config around to make this more reasonable. I didnt realise that there is no point in having the burnout rate configurable. I will convert this field into a boolean, since thats what it actually is.