As Ahl as-Sunnah wa al-Jama'ah we affirm the Attributes of Allah that reach us through authentic narrations without attempting to understand their "how"ness. First I will quote what the scholars say about nuzul, then get to your question with that context in mind.
Al-Lalikai records Imam Ahmad as saying "He descends as He wills, according to His Knowledge and Power and Greatness. He encompasses everything with His Knowledge." And there are dozens of narrations from the Sahaba affirming this, and not trying to interpret exactly how this is done.
Imam al-Ajurri said, under the chapter "To have faith and trust that Allaah descends to the lowest heaven every night"
"Faith in this is obligatory, and it is not allowed for the
intelligent Muslim to say , ‘how does he descend?’ - and none would
answer this except the Mu'tazila [for example the saying of some, that
His command descends, and the saying of others that His angels descend
etc.] As for the People of Truth, then they say, ‘faith in this is
obligatory without asking how. Because the narrations are authentic to
the Messenger (SAW) - That Allaah descends to the lowest heaven every
night and the ones who transmitted this narration to us are the ones
that transmitted the rules of halaal and haraam, and the knowledge of
salaah, and zakaah, and fasting, and hajj, and jihaad. So just as the
scholars accepted these from them then like this, they accepted from
them these sunan. And they said, the one who opposed these is horribly
misguided. Warning him and warning against him."
Now we have other authentic narrations (and ayaat in the Qur'an) stating that Allah SWT is above the Throne. Affirming this does not imply denying the hadith on nuzool, nor does affirming nuzool deny the Attribute of being above the Throne. We negate the "kaif" of both of these because we don't know and can't imagine how they work (Allah is not like anything we know of).
Abu Ja'far at-Tirmidhi said "The Nuzool (Descent) is understood, but the how/nature is unknown, and faith in it is obligatory, and to question about it (i.e. how) is a bid’ah."
So getting to your question, the issue with it is the premise inherent in the question - ascribing a how to Allah's nuzool, and insisting it must correspond to our three-dimensional world where the Earth is a sphere, and how our concept of time is that a day is 24 hours and it is necessarily night always somewhere on Earth, and all these other assumptions. The truth is that Allah is not bound by any of these. For example, think of a four-dimensional world in which the Earth is just a manifold. To make it even easier, imagine a "world" that is in 2-D only, but you can see it in 3-D. Now to you, this "world" is just a plane, but within that world they have directions and such. For us there is a well-defined notion of how close something is to that plane, but the inhabitants of that world cannot understand that notion of closeness because they don't have another dimension to imagine it in! So you might be 5 inches away from that world, or 50 feet away, but for them they have no idea because they can only think in terms of north, south, east or west. It's all the same to them whether you're close or far in the third dimension. You can insist that you're closer at 5 inches, but they wouldn't know it or have any way of measuring it. Now throw in the notion of time and it gets messy real quick. I'm not saying that this is how it works, I'm simply presenting this as an example of why it's futile to understand things in our 3-D perception of everything.
My point is that there is a lot we cannot imagine and don't know about, and so it is safest to affirm without ascribing a "how" to it. Read "Hyperspace" by Michio Kaku to get a glimpse of what can happen in our universe without us being able to grasp it.
(quotes from Imams of the past from here)
