OK. But I just want to point out that FWIW, you said you don't like the image of a Kahler because it is associated with a genre you don't really like. Then the first genre you named that you do like (alternative) has Jerry Cantrell as one of its top two most known and respected guitarists. Well guess who is famous for playing a guitar with a Kahler vibrato (and is perhaps the most famous guitarist who is heavily associated with one)?
I don't dig heavy metal either, at least not from the period that is heavily associated with Kahlers (I pretty much like classic metal only, i.e. '70s metal). I don't like any guitarists who use one. I am mostly into old black American music, and the white rock and pop that is based on it – even less "wanky" than what you listen too. But the Kahler is simply a fantastic vibrato, period. It can get good use by almost any guitarist in almost any genre. And it will provide you with the easiest installation, the most adjustability, the highest build quality, and the most Mustang-like action of any other vibrato you could use. It solves all of your problems, except for your hangup on the way it looks.
The body thickness you posted explains your valid reluctance to installing a Mustang vibrato. I had no idea that the '90s MIM Duo Sonics were even thinner than the old 1 1/2 inch ones from the '50s through the '70s. If you really are at only approximately 1 5/16 inches thick, you definitely don't want to install a Mustang vibrato, which requires a 1 1/4 inch depth. That leaves you with only 1/16 inch padding. You need a Kahler or a Bigsby or a Stetsbar.
You don't need to remove the stock switch. You just need to add a phase reversal switch to one pickup.