While I can understand you wanting autosave on in your situation, I much prefer autosave off because I often open files to see what is in them and do not want to automatically modify them just because I accidentally hit a key and delete it. Automatically changing stuff is a choice you should have to make, not a feature that I have to race to disable.
Pretty vague question.
One assumption that "mathy types" like to make is that the slope be negative-proportional to how far the value (not slope) is from the desired target value... and then you get an exponential decay (buzzword). But there are lots of other assumptions one could make... some of which lead to PID control (buzz; very mathy stuff).
But these days you could use a neural net (buzz; so mathy they don't usually pretend to understand what the NN "learns") or fuzzy logic (buzz; which is ideally intuitive but has many surprisingly mathy assumptions) to make the behavior nonlinear and go to the desired result much faster... so really, there are many many possible answers. Maybe you can watch some ELI5 videos about these buzzwords and refine your question?