yes, I was reaching deep in imagination to find some parameters which would favor the non-spin boat sailing the shorter course (like DDW) as faster than a spin boat.

Only by reducing upwind speed significantly (like removing jib altogether) would there be enough time delta for the spin boat to not be able to make up the time/distance downwind.

In my anecdotal experience, only time DDW works is when it's so light that the spin boat never reaches hull speed. As in less than 5 kt breeze.

Also noteworthy is most boats add a spin to the sailplan without reducing other sail area(s), unlike your example of reducing upwind area and adding downwind area. But that may be worth thinking again, since your discussion shows a little tweak in upwind sail area could develop quite a ratings beater...