Update - I figured out a way to do it with Named Ranges and Array formulas...

I went with Option 2 above and renamed my ranges to have them just time-based (inclusive of all geographies). I then used various nested IFs can calculations all based this general format: {=SUM((Named Range)*(Geography=A1)}

Question since I'm new still...since I answered my own question, do I edit this thread as solved? I'd still be curious to hear other thoughts with other approaches etc, but I want to be a good citizen around here.