Heavy handed ? lol, that does not blow fuses. To prove this I’m playing my 3.7i at around 100Db and taking a video. I posted it to youtube. It is not power that hurts any speaker, its distortion.I assumed we were talking about stock factory Magnepans? The link you posted to above, show speakers that are very far from "factory stock". Who knows what perimeters have been changed with all of your modifications?
Also, why spend the money on this "kit", when you can pull off the back plate and easily rewire the connectors to bypass the holders. This can be reversed if/when you need to. It creates a much shorter and better path than using jumpers and special fuses.
So if your talking about better fidelity, (which you are), then there are cheaper and better sounding options.
If any members are in Northern Colorado, I would be more than happy to perform this tweek for free, just get a hold of me.