Damn, Joey, you beat me to it. I was busy writing my own so-called short version of a response, and checked before posting. So now I have to revise a little...
But first, we can't ignore protocol: Welcome, Steve! Since you're new to the group, I'm guessing this might be your first Alembic? The other clue is that you cross-posted to another topic, and after you've been here even briefly you'll realize that's not necessary - most of the group seem to read everything that shows up regardless of topic, and you'll almost certainly get a number of interesting responses (though some might be a bit puzzling at first..).
I happen to play fretless myself, though personally I'm trying to mostly avoid the classic fretless tone, and I can't imagine using d'addario chromes... so maybe I can help .
Back to you, Joey. As usual, you've written a great description of how to adjust pickups and gain. In fact, it's the first time I recall reading about the possibility of angling the pickups along the length of the strings, rather than just getting them closer to the low or high strings. It's a *really* nice touch that the mounting system allows for this. When I started playing with it myself a couple weeks ago, I mentioned the great sound variations I was getting by tilting the pickups towards the neck or bridge to Mica, and she said Of course...
Oh well, it doesn't matter who figured it out first, as long as we all understand the potential. Personally, I favor having the pickups (FatBoys in my case) almost as far as possible from the strings (for a cleaner sound), about a 1/16 closer to the B than the G (so I can play equally hard on the higher strings without sounding too bright), neck pickup tilted way back towards the bridge, and bridge either neutral or tilted slightly towards the neck (seems to help with more even timbre up and down the neck).
But I think these sorts of adjustments are more related to tone/timbre across the strings, and up and down the neck. I think the question about mwah is a little different, and that's why I wrote the rest of this not-so-short version.
Steve: the first step is to be clear on what you mean by mwah - and have you been playing fretless for a few years, or is this a relatively new thing to you?. If I understand what you mean by this, it seems to me it mostly comes from low-level string buzz against the fingerboard. In my experience (so far), this tends to depend on (a) bridge height, (b) neck relief (bend), (c) how carefully you intonate, and (d) how your strings respond to fingering pressure and intonation accuracy. Not necessarily in that order, and there are undoubtedly other factors such as fingerboard surface, etc, but it's a start.
I would work through all of that before bothering with pickup adjustments. Unless your pickups are grossly angled (in terms of distance between the pickup and the strings at the E and G sides), that's not likely to matter much for mwah.
To clarify, the first experiement I would suggest is to raise the G side of your bridge by half a turn of the allen wrench (a lot, but that's okay). Do you lose much or most of the mwah on the G and D? If so, lower it part way back to where you start getting some again.
Now, without any of that fretless sliding stuff, play a note somewhere moderately up the neck (7-9th fret area or so). Play the same note a bunch of times, altering your finger pressure and shifting your intonation very slightly. Does the mwah go away if you nail the intonation and press firmly, but appear if you play with lighter pressure or perhaps ever so slightly off pitch? (Do this on the G and D, where you know you like the sound.)
If the bridge height made a big difference on the G and D, then to improve A and E mwah, there are two things you should experiment with. The first, of course, is to lower the bridge on that side. The other thing you'll need to investigate is neck relief, because getting this sort of buzz, in a tasteful way, is a pretty sensitive thing. Fortunately, since you have dual truss rods, you have some flexibility here (Joey would use uppercase here, and he'd be right).
From what you're describing, it sounds like you would want to lower the E side of the bridge, and/or straighten the neck a little on that side (i.e. tighten the truss rod on that side by maybe 1/8 turn or so). To get a better idea, hold down a string (first the G, then the E) at both the 1st and 24th fret positions, and note the gap between the string and the fingerboard at the 7th fret. If you see a noticeably bigger gap on the E, tighten the truss rod a little on the E side.
(I encourage you to jot down some notes about the adjustments you make, so you can reliably get back to your initial settings.)
If none of this helps, then we could start talking about strings. It seems to me you'll always have more trouble getting a similar mwah from the fatter strings, because it's a fairly subtle thing - not quite the same as the more typical fret buzz - and the finer windings on the skinny strings work better for this. Having even tension across all the strings is also important - if you have a relatively floppy E string, by the time you get it low enough it's going to end up slapping the board instead of giving a nice subtle buzz. Different strings might work better for you, but this would take more work and patience (and some cost).
I suggest you try the bridge height and relief adjustments first, and see how that goes. And by all means, play with your pickups a little. Then we can talk more.
This is quite amusing to me, because just last night I was very pleased to eliminate what I think you're looking for on my G, by raising the G-side bridge about 1/4 turn and loosening the truss rod less than an 1/8. And with flat wounds, I think I had a mwah you would have paid extra for... Be interesting to hear what you find.
-Bob
(Fretless Old Guy, are you still lurking out there? You must have some useful thoughts on this subject.)
