Great tutorial. The iOpener did nothing for removing that glass backplate, it needed higher heat. I used a hairdryer on the hot setting and didn’t have to break out the heat gun. Try the flat picks rather than the opening tool to work your way under the edge, as they’re thinner.
The iOpener was more useful in applying constant heat to the screen while trying to remove the old battery.
Tip: when putting the upper antenna shield assembly back in, pay close attention to where the screws go — there’s a hole that looks like a screw hole but isn’t. I hope I didn’t damage any circuitry trying to put a screw in there. The phone still boots up and functions, so fingers crossed.