Sorry for the delay. And thanks for the patience!
You are confused for a good reason. After I began formulating an answer, I realized that I needed to get more details on the configuration. During the experimentation, I realized that my setup worked okay but only for the NORM normal mode. When I tried to do the setup for the ST stunt modes I realized that I wasn't getting any negative pitch. Fine if I never intend to use it but I know that was one thing you were working on. So here's what I discovered:
The pitch wasn't going negative because the SWASH MIX was way too low on the Pitch component. It went positive ok but only for about +10 degrees at maximum when I had the pitch curve heavily tweaked. The ST mode pitch curves never developed negative pitch.

So I started to experiment again and I've come up with a SWASH MIX the gave more to pitch. Also, to keep AILE and ELEV at an even keel, I turned them down. Again, this is after fiddling for a day and is subject to change but I have
AILE (+) 60
ELEV (-) 60
PIT. (-) 50

I had a higher value for pitch (-70) but discovered that, while I could get it to work for 50% stick = zero pitch, the resulting performance was VERY hot, beyond my tolerance (it went from no lift to jumping 5 feet instantly). So I reduced it a bit and then did the pitch curve trying to find the level where pitch was really zero. Unfortunately, that is NOT at 50% stick. But at least I'm a little closer and might change things as I get more bold in Stunt Modes. Right now, I'm just happy I got -2 degrees pitch in NORM mode.

NORM pitch curve
Point-L 29% (about -2 degrees
Point-1 29
Point-2 35.5 (about zero pitch)
Point-3 INH
Point-H 100
EXP OFF (The LHS guru said he didn't recommend expo so I'll get comfortable without them for the moment).

Now one of the side effects of a reduced PIT. in SWASH MIX, the zero pitch is not at 50. So I have to depart slightly from the linear 0-100 setting. I set the mid point Point-2 at 37 (for some reason, zero pitch is just a little different between NORM and ST). All others are default. This lets me get the same lift and throttle when switching from normal to stunt. I haven't tried this in flight, mind you. Just holding on for dear life to the model on the workbench.

Throttle curves are unchanged and about what you use (though I'm tweaking my 50% stick throttle in NORM to about 70% so I get a little more stability - that is also why the lift is a bit twitchy so that might change.....)

Let me know if this is a little closer to what you expected. I flew it as a test and that's when I discovered I needed a little more gradual lift on takeoff (busted my skid support on the frame). If I keep having to replace the frame, I just might investigate the SUPER-SKIDS.com . The skids are expensive ($25) compared to regular skids but when combined with full rebuilds to replace the frame, my time is getting a little more valuable. Then again, maybe I just need to get a lighter touch.

BTW, I've been trying out exponentials in the aileron and elevator in the Dual Rate switches. Actually using negative EXP (-25%) to try to get more sensitive than the linear mode. This is for experimentation only. I've got two flybar weights on each side, which slows things down a bit and the EXP puts it back - even LHS guru thinks this is silly but I know I am still a little to overreactive when things go bad.