Trackpad not physically clicking after cleaning

Hi all, ever since I bought my Early 2011 15-inch MacBook Pro, I hated that the trackpad seems to stick out ever so slightly at the top, while the bottom of the trackpad is slightly recessed into the casing. It's only half a millimeter at the top and one millimeter at the bottom, but it's still noticeable. So I thought: why not take it apart to see if I can do something about it.

Everything went very well, until I tried to reseat the trackpad into the case. I used four stickies to properly align the trackpad. But after multiple hours of trying different combinations of the bottom and top screws, I was never able to make it 'click' like it did when I took it apart. Now, I have to use quite a lot of pressure on the bottom center of the trackpad to trigger a mouse click. It doesn't make a mechanical 'click' sound anymore. While it did so perfectly before I took it apart.

I already checked the button at the bottom of the trackpad itself, and that seems to click down just fine.

I also couldn't resolve the issue of the trackpad not fitting in properly, every time I screw it in place, it will always stick out at the top of the case. I only wiped the trackpad down and I made a small mistake while following the guide: I accidentally loosened up the black screws at the top of the trackpad hinge. I screwed them back down.

TL;DR: After taking a good, working trackpad out of the Mac, it only registers a mouse click in software when I firmly press on the lower middle of the trackpad. It doesn't make a mechanical 'click' sound anymore. Even after hours of fiddling with the alignment and all top and bottom screws.

Because some things are hard to explain, I hope that this image makes the problem clearer.

Well, I took the whole thing apart again. For my own sanity, I removed everything that had to do with the trackpad to 'figure out' what each part did. First I removed the small silver tabs at the top of the trackpad. I inspected them against some images of new ones I found online. They look nearly identical. I also removed the trackpad itself to see if it maybe was bent. And while there is an ever so slight curve in the center (about 0.005 mm difference with the edges of the trackpad).

I also removed the big shiny screw that's supposed to handle the button in the bottom center of the trackpad, and inspected the button itself. Both look fine to my eyes. I also tried pressing it with a screwdriver, and it clicked like it was new.

Then, I tried to line up the trackpad as good as I could. None of the edges have any friction. But when I tightened the silver screws at the top, this happend.

So, I loosened the silver screws, positioned the display at 90 degrees, and laid the bottom case on my desk. While applying a lot of pressure, I tightened the silver screws again, but, because of the pressure, the trackpad couldn't go up much at all. After doing that, the trackpad is still 0.05 mm higher than the frame, but it's much less than it was before.

Next, it was time for the set-screw (big silver screw at the bottom center). Long story short, I can't get it to click normally. Right now, I have it set where the trackpad has just enough freedom to move and make a (really soft) 'click' sound, but I have to apply quite a lot of pressure to let that 'click' register in software. It doesn't matter how slow I turn it, it never goes back to that loud 'click' sound every MacBook user if familiar with.

This is the full trackpad assembled in the bottom case (without set-screw):

Well, I took the Mac apart one again to check the button at the bottom of the trackpad (the small silver nub). I tested it while the Mac was booted into OS X. The button works like a charm. I have to put very little pressure on it, and you hear a loud 'click' that you suspect from these MacBook trackpads. The mouse click in software activated immediately once you hear the 'click' sound, as it supposed to be.

Next, I completely removed the silver screw at the bottom of the trackpad (the adjustment screw) and tested the trackpad, while the Mac was still booted into OS X. I tried the trackpad again with every 5 degrees I turned the screw inwards. I always have to apply quite a lot of pressure on the glass surface to activate the software click, but I never hear the button 'click'. The trackpad itself doesn't make a 'click' sound at all, apart from a very muffled sound which does not correspond to the button being pressed, since it doesn't register the 'click' in software.

NOTE: The bottom case was not screwed in when I took the pictures, that's why it may look strange from the sides.

Next, I checked the chassis of the Mac, as suggested by @danj. As far as I can tell, the frame is completely straight. The ruler doesn't have any wobble.