Maybe I'm missing something here, but rather than actually shortening the shock, all the updated spring perch does is reduce spring tension and increase sag (depending on preload adjustment).
Just dropping the front forks turns the cornering handling to crap at lower speeds (oversteer), and does not increase the rake when braking and the rear shock is unloaded enough to top out. The added sag would increase rake due to spring tension and not mechanical compensation under regular shock loading conditions.
If an internal top-out spacer/travel limiter were installed internally, the spring perch would bring the spring rate back into stock range, and increase rake back closer to stock. Another alternative would be to reposition the mounting point(s) of the standard shock, but that would take altering the swingarm, frame, or both; a last resort.
I have little choice but figure out how to drop the seat height; after a very major lower back surgery, it is all I can do to get a leg up far enough to get on without a step, and I look like a drunk getting off. The bike is a '21 S.