Wow, this is a crazy neat idea. Can't wait to hear/see more!
I really like the idea of the small trim pots. You can always make an adjustment if needed.
About the extra adjustment if needed, I realized that when I had my Floyd off, I accidentally lowered the action a wee bitty hair, and that of course affected the tone before my sweetening. So I'm going to raise the action a little bit then see if I need to readjust the trimpots to sweeten again; I imagine I'll need to reduce the sweet to add back a hair more clarity after raising the action. The guitar plays great with low action, but really low action just never sounds as good to me; I never measure; I just raise it a hair until it feels and sounds right. I'm also thinking about making a big change to a new pick. I keep a cache of various picks around that I whip out every couple of years or so, and I decided to whip it out yesterday. I was shocked to find that the one Fender 351 Heavy pick I had in that huge array may have been the best sounding one to my ears, compared to my Dunlop Tortex Standard .60 that I've used for a while. That Fender just had a great attack that I loved last night, but I don't know if it's one of those picks that only sound good when a little worn, so I bought a 12 pack of them last night, and I'll compare fresh Tortex with fresh 351s. Once I make a decision on the pick too, I'll adjust the sweetening to fit it, and I'll be set.
That's the other thing about being able to tune resonant frequency by ear on the fly, pick attack will change greatly with the pick you try. So maybe you find a pick that's really comfortable, but it sounds like dogshit. Well, maybe if you retune the resonant frequency of your pickups, all of a sudden that pick may sound great with your guitar. In fact, that makes me want to try tuning the resonant frequency to the Dunlop Jazz III 1.14 that I have. That thing really lets my wrist loosen and fly, so maybe I oughtta just try tuning to that pick first. See, I'm just thinking out loud here! This has opened a whole can of worms to me. It makes me feel like, with any passive system, you can just take a guitar, a model / gauge of strings, a pickup, or a pick that feels great but maybe didn't have the tonal mojo you wanted, and with the right tuning, if your pickups are close enough stock, you can get the mojo out of them.
I mean I didn't even take a second to balance the pole pieces, as I had done on my most recent pickups. I can imagine that will only further perfect the output.
One thing also to keep in mind: I found that as I was sweetening, I was able really to hear more finely if the pickups needed to be raised or lowered to match each other's output, so I was playing with that at the same time. And I forgot that you're using these same pickups Scott, the Saturday Night Specials. I feel like, if I could get them to sound good in this bright guitar, they truly can sound great in anything, with the right tuning.
This is also the kind of thing I can see, in a more nuanced way, curing the hatred of those of us who found, e.g., a Duncan JB to be a shrill hatefist. This could also be the ultimate tool to balance and HSS set. Man, for an HSS, you could have one trimpot in parallel, as I've described, to sweeten the resonant frequency, then another in series, between the humbucker's hot and the volume knob, to lower it's output to match the single coils. It's so the idea of taking what is unchangable, the resonance of the wood of the guitar and its construction, and tuning the pickups to be as receptive to the pleasing resonances in that guitar as possible. I just keep thinking that maybe this would keep you from having to get rid of a guitar that sounds terrible but feels great. Because I really feel like my guitar, without the sweetening, really took way too much processing to sound good. Now that's not a problem at all. It's just sitting right with all the amps I've tried so far.