If it blocks a pixel of two, you're only going to notice on the camera border "L"s. It's really an overblown issue.
Regarding install, even if you intend to take the apple sticker off and install right away, I would still wipe the phone to remove any possible residue from manufacturing. I then cover the screen in painters tape, remove and place the tray on immediately. I also do it in a bathroom after letting it steam a bit and I use latex gloves to keep my hand oils off. An extra large microfiber cloth also helps to clean the screen after using the included wet wipe or isopropyl alcohol wipe to remove any streaks.
Personally, I think I want to check that screen is OK with no marks or dead pixels before I install the protector.
Regarding install, even if you intend to take the apple sticker off and install right away, I would still wipe the phone to remove any possible residue from manufacturing. I then cover the screen in painters tape, remove and place the tray on immediately. I also do it in a bathroom after letting it steam a bit and I use latex gloves to keep my hand oils off. An extra large microfiber cloth also helps to clean the screen after using the included wet wipe or isopropyl alcohol wipe to remove any streaks.
Personally, I think I want to check that screen is OK with no marks or dead pixels before I install the protector.