Unlike photo plants, auto's start flowering according to age, and they have a fairly specific window as to when they can be harvested for optimum yield/potency. They are genetically given a start and "end" date. the light cycle will not change this. The optimum window can be somewhat subjective, from grower to grower, depending on preference, but if a breeder says 75 days, it is usually within a small window on either side of that. Visit a few of the grow journals here, and you will see that 20/4 seems to be the go to schedule for most. And while your formula, in theory, has some awesome possibilities, remember, keep it simple. If you want to try it out, go for it, and then at least you will know, for yourself, vs just relying on someone else's word for it.
I have grown photo strains for quite some time, and am still very new to AF strains, so i may be somewhat mistaken. I am giving my 2 cents based on 98% what I have read, and seen on this site, and 1 auto plant that i have grown.