Tha'ts great planning on your part.. I'm likewise frustrated with the inter-city dynamics. Not intuititive, and often not functional.
I agree, small city map size can work, but not if the cities don't function together properly. I can't even get utility sharing to work consistently.. there seems to be a cap, where my cities refuse to import any more power, water, etc from the next town. Anyhow, I hope your issue gets solved! and mine..
Yeah, I completely ran out of space, becuase I had to build a (MASSIVE) university with add-ons to get my (MASSIVE) processor and consumer electronics plants to function. And you have to build a TON of them to get your electronics HQ fully upgraded. I had to bulldoze all of my industry just to get enough workers at the plants.
