Live preview mixed

[ice-fly]

Lets say I have a 75 step long diffusion, and i have Live preview display period:

1. Because the start of the diffusion is a low resolution of the final product TAESD makes sense for the first preview at N=20,
2. Because the middle of the diffusion has more info about the final product approx NN makes sense for the second preview at N=40,
3. Because the end of the diffusion is very close to the final product full makes sense for the third preview at N=60,

How might someone implement this? what parts of the existing code would need to be modified? If i wanted to write an extension to do this would that be possible?