Absolutely, the terrain comes into play.
:ditto: Definitely. I've seen that mentioned a few times - maybe even in one of your links from further up the thread, although I'm starting to lose track of what I read where.
I think I've also read that localised weather conditions can play a part in signal strength and result in a phone connecting to a tower which isn't necessarily the closest geographically. (but please don't ask me to try to find the link for that again!)
Meanwhile, I've stored up the last few posts to digest later.
I think they call for a proper sit down with a cup of coffee, rather than a quick browse on my phone in between appointments!