That, or the watchmakers of old didn't have to worry about wiring actuators, speakers, and heart rate monitors on the back plate. Or is that against nature and shouldn't be done in the first place anyway?

For what it's worth, my F91W has Philips screws on the back plate exactly like this and I never had a problem, and I've taken it apart more than a few times (it's a Sensor Watch!)

I understand, and don't have any of those tools to hand.

It sounds like this is not a watch for you.