how would the size and shape of the sweet spot be different if the tension is, let's say, 24V:24H as opposed to 23V:25H?
Type of racquet ? Oval or iso? I am guessing here - oval shape racquet - oval shape , iso will produce more circular. Tension combi 23x25 more oval than24x24 - area wise should be the same
Or alternatively the sweet spot size might not vary at all; only how effective the sweet spot is ... It might depend on how you define a sweet spot.
At a pure guess, I'd say that the difference in performance is inversely proportional to the length of the string, so 24/24 would be more effective. But really, you need a science lab