Do you have any advice? Other than use the right size screwdriver and the gasket goes on both sides?
Ok so that was actually all I needed! And I went and got a 1/4" socket to use the #3 drill bit with, to give my noodle-arms (weak) some leverage.
Ok, so I pulled it off, I put the gasket on both sides of the opening, and I screwed it in as best we could, but it was still leaking.... it's dark but I'll try some photos...
Because I hadn't screwed it down tight enough. They are self-tapping screws, and the first time I put it on, it didn't tighten down and leaked because the gasket was only on one side of the wall.
The second time, we didn't use the correct screwdriver size (because I wasn't about to use the cordless on it from outside the pool when the water was higher... using it while I was inside the pool was bad enough...)
My theory is that when we put it back on, the screws went in ok by hand until they reached the point we'd stopped at the first time. They still had to go in farther to seal, but between having to tap the hole for the first time after that point, and needing to compress the gasket, they were too hard to turn from outside the pool with the wrong screwdriver.
2 things I now know i did wrong: 1) there was a longish piece of liner that ended up folding over the wall cutout in the center under the gasket and 2) I did not install the screws from the center outward.
Nope neither of these mattered... it was in fine, and my method of doing corners then each one a little bit one side then the other seemed to be fine.
I'm still not sure why the gasket is pulled away from the skimmer so much given how tight it seems to be...
It wasn't tight, we'd just reached the point we had to start tapping the holes again and that was when the gasket started resisting.
I foolishly didn't look at the inside of the skimmer to make sure I was actually screwing into all the correct holes and not making my own, so now I'm worried I need to order a new skimmer because I've messed up the inside of this one.
It was fine. I talked it through with someone and realized I couldn't tap new holes in the support fins or other wrong parts inside the housing for 18 screws when they were flat.
After typing this up, I went and checked it to get a "not leaking" picture and found a tiny slow leak.
I gave up trying to tighten it more (we got it down to an even slower leak, but tightening it would make it slow more, but then speed up again when a different one was tightened), and bought pool putty. Had to get it from Leslie's because the hardware stores had nothing in stock, sadly. The resin part was partially hardened, so that was fun, but I got it mixed and sealed between the faceplate and the back of the skimmer. That reduced it to one super super slow drip in the back.... so I also sealed the whole bottom of the skimmer. Not sure I would have gone the pool putty route if I didn't have the stainless panel, honestly.
It's not leaking now! I'll add a final picture to this post after work tonight!