The right way to do that is trains. A fully compressed, stacked belt is 960/s, but a train can easily hit that throughput as well (and even exceed it). And they are much easier to set up across long distances than belts are.
And a track is two spaces, thus two belts can fit. Even just blue belts gives 1440/s for the same space.
Your first item delivers a lot faster with trains, and when you're dealing with stuff that spoils the faster transit is a big benefit, but for the most part I find trains underwhelming other than on Fulgora where you don't really have a choice.
Eg you don’t need city blocks making circuits, just pipe in molten metal and make them with foundries and EM plants. And then you also get steel, copper wire, gears, whatever else you might need.
There are a few exceptions of course, like lubricant for electric engines, but it’s not nearly as complicated as it was pre Space Age.
edit: It does seem to be 240/s: https://wiki.factorio.com/Transport_belt_capacity_(research)