I just installed the Hayward skimmer on my 15' Intex pool and it's working great. I followed HacoboPablo's excellent photo tutorial in this thread with a few small exceptions based on suggestions also in this thread by laceygirl and poolsam. The main difference was not splitting the butterfly gasket. The other differences were adding a ball valve and using an adapter rather than a hose clamp.
I first installed the skimmer on the pool without the gasket. I screwed it down nice and tight so it wouldn't move, then cut out the liner with an X-Acto knife using the inner plate as a guide. After cutting the liner I removed the skimmer and then reinstalled it with the butterfly gasket in place.
I did the entire job by myself and it took about 2 hours, which included the time to drain and refill the water. I probably could have done the job faster with a helper, but I worked slowly and carefully so I wouldn't mess anything up. Most of the job I did from inside the pool. It's scary working with sharp tools in the pool so I was extra careful and I really took my time. I wore thin rubber work gloves for a better grip on my tools so my wet hands wouldn't drop a tool or slip and make an extra hole in my liner.
As I said, I did not split the butterfly gasket and I'm not sure why you would want to do that, except maybe to avoid installing the skimmer twice. Yes that was a minor pain, but I think it's worth it because the installation seems cleaner this way. The butterfly gasket fits easily into the hole I cut out of the liner and the screw holes in the gasket all lined up perfectly on both sides of the liner, so reinstalling the skimmer was actually quite easy.
After the final installation of the skimmer, I added a Hayward ball valve directly below the skimmer so that I can turn off the water coming from the pool in case I ever want to disconnect my hoses without draining the pool.
I also wanted to avoid using hose clamps. I wanted to connect my Intex 2650 sand filter hose directly to the Hayward ball valve, so I bought these adapters from Doheny's. They come two to a pack so I have a spare. They included teflon tape but I didn't need it. I could have made my own adapter but these work perfectly, though I admit they are a little expensive.
http://www.doheny.com/poolsupplies/Intex-Pool-Replacement-Parts-And-Fittings.html
Here is what the finished product looks like. It's a huge improvement over the floating Intex skimmer. Also the Hayward comes with a vacuum hose connector which makes vacuuming the pool so much easier. I'm very happy with my new skimmer.
