U.Pacific, I am not an electrical engineer, but I think your thought process makes things very complicated.
Let me start at the beginning. You did not say what kind of and how many panels you had and their output.
Just for argument sake let's say you have 2 panels of 100 Watts each. If each panel can produce 100 Watt at 12 Volt, then one gets approx 8.3 Amps per panel on a good sunny day and if the manufacturer or their marketing guys have not told any lies.
Now you have the choice to connect those panels in series, which will give you an output of 24 Volt and a max Amps of 8.3 Amps or....
you can connect them parallel, and then your output would be 12 Volt and 2x8.3=16.6 Amps.
In BOTH cases the wattage remains the same: 200 Watt.
From reading your post it seems you have a solar controller that can double or half the Voltage. Really, it does not really matter what kind of controller one has (for this part of the discussion) as the output can not be be bigger than the input (200 Watt). In fact there will be electrical losses etc. So the output would be around 180-190 Watt.
The only advantage I can see is that when you operate on 24 Volt (as opposed to 12 Volt) there will will a smaller voltage drop in the electrical circuit, but if your wiring is designed properly the difference would we close to nil. BTW, 'voltage drop' in a wire is loss of power ie the wire is getting hot.
Assuming your diagram is correct, I think your suggestion makes it much more complicated, and complications is something to be avoided, especially when there is no gain.
Now, looking at your diagram, you would have to add 4 or even 6 high amperage switches. They are pricey and again, will cause voltage drop.
And then there is the problem that while all 8 batteries are charged at the same rate (at 24 Volt), your appliances (on 12 Volt) that will run during the day will only be drawn from from one set of two 6 V batteries, causing an imbalance that can only be rectified by putting all 4 sets of batteries parallel: that is at 12 Volt!
If the prime reason for your suggested diagram is that your solar controller cannot handle the amps at 12 Volt, then I suggest to buy a controller with a bigger capacity. That could be cheaper than all that switchgear and the heavy duty wiring associated with that.