I would be more than happy to help.
No I did not re-enforce the sidewall of the pool. Nor has anyone else here who installed this skimmer that I am aware of.
I am going to outline EXACTLY how I installed the skimmer and if you follow these instructions you should be good.
1: Drain the water below where the bottom of the skimmer will be.
2: Place the faceplate for the skimmer inside the pool and position it where you want. I put mine just below the grey seam.
[attachment=2:2yfvcl4t]skim1.jpg[/attachment:2yfvcl4t]
3: Hold the faceplate and with a marker make marks for all the holes in the faceplate.
4: Poke two holes in the liner with an awl or screwdriver a little bit smaller than the holes on the faceplate. I used the two top outer holes to start with.
5: while holding the skimmer on the outside of the liner, install the top two screws through the faceplate and into the body of the skimmer, I tightened them enough to hold the body of the skimmer.
6: Now continue poking the rest of the screwholes through the faceplate and the liner and one by one install all 10 screws and snug them down.. Dont overtighten them!!!!!
7: Once all the screws are in, and tight enough to hold the skimmer body and faceplate together, take a small exacto knife and trim out the liner by following the faceplate ring.
8: Now dis-assemble the faceplate from the skimmer again, remove all the screws carefully while supporting the skimmer box.
Keep in mind these screws are hard to screw in and out, this is normal.
9: Once you have the skimmer and the faceplate out of the pool, take the butterfly gasket "BUT DO NOT CUT IT" separate the gasket by gently pulling it apart, you will see that the middle section is joined together. Place the gasket in the newly cut opening, one side of the gasket goes on the inside of the liner, and the other on the outside of the liner.
10: Once you have the gasket in place, replace the faceplate, and the skimmer body together and start the two top screws, screw them in until they pull the faceplate and skimmer body together but leave them a little loose.
11: Install all the other screws and get them close but DO NOT TIGHTEN them all of the way. Once all the screws are installed you can then snug them up, DO NOT OVERTIGHTEN the screws, go in a cross pattern on your final tightening of the screws until the skimmer and faceplate are snug together. Remember you can always come back and snug them up a little more if they seem loose to you BUT DO NOT OVERTIGHTEN them or you will have a leak.
[attachment=0:2yfvcl4t]skim3.jpg[/attachment:2yfvcl4t]
12: Install the stub on the bottom of the skimmer after wrapping the threads a couple of times with teflon tape, place your hose on this stub and tighten down the hose clamp.
[attachment=1:2yfvcl4t]skim2.jpg[/attachment:2yfvcl4t]
13: Fill the pool back up with water, checking for leaks around the gasket as the water makes its way back up the side of the pool. Chances are you will have no leaks, I keep my water level about halfway up the front of the skimmer. If you notice a leak, gently snug up the screws near the leak but do not overtighten!!!!
The BIG warning, dont be scared of this install or cutting the liner, take your time, make sure you follow these instructions to the letter, and DO NOT OVERTIGHTEN the screws and you should be fine, REMEMBER you are trying to bring the faceplate and skimmer body together WITHOUT squeezing the HECK out of that gasket. Keep in mind also that those screws are hard to turn and this is normal, use a HAND screwdriver and not a screwgun or drill.
As for the other outlet, I just left the Intex valve in place and closed it off. I will make a return out of it next season.
Hope this was helpful.