Questions on Sorting Systems

Hello everyone, I've just finished the first segment of a sorting system in my world and now I'm left with an interesting decision: How do I decide what to sort with my currently limited sorts (84) and how to organize them within the system?

The system is organized as a square with 21 filters per side. I'm intending to build further layers below the current one until I can sort all stacking blocks but that's going to take quite a while and in the meantime I'd like to start enjoying the fruits of my labor.

So, how do you decide what to sort and where it's sorted within your system?