That's really cool
@DanQuayle! I've wanted to try something similar and play games where I completely ignore one of the big three districts. I think fast science victories can be achieved completely without Commercial Hubs as well. Without Campuses it would be difficult.
Since we're at it, let me ask: How many early campus districts do you build? How early? In beelining techs like industrialization and the spaceport tech, do you aggressively do it or wait for the eureka?
As soon as I reach writing I at least place a Campus in all the cities I have at the time. Unless I can very shortly acquire a tile somewhere that gives much better adjacency bonus, then I might wait a bit. How many and how early depends, but usually the first 3 districts I complete are Campuses.
On the beeline towards Industrialization I usually complete all eurekas but Sailing and Shipbuilding. Often I get Sailing as well, but I wouldn't choose a worse spot for a city only to get it. From Industrialization to Electricity I complete none of the eurekas. No Harbors, no Musketmen, no Privateers. I might try to change my strategy here so that I do build the 2 Harbors somewhere instead of 2 Commercial Hubs, just not sure when to fit in Astrology and Celestial Navigation. The Eurekas I usually never complete from there on the way to Rocketry are Sanitation, Chemistry and Radio. Flight I have maybe once got from early Ruhr, but mostly that would be too late. Scientific Theory eureka depends on culture rate. Sometimes I get it in time, sometimes not. Great Scientists can help a lot with the random eurekas they give. Seoul can also be very helpful. I've often used Galileo (250 science per adjacent mountain) to tech Electricity.
Also, in waging war: I think I'm ok, but how do you do it? In terms of number of units and composition? In "being aggressive", do you attack multiple cities, civs or city states at the same time? In aiming for 20+ cities, when should I have these? In my experience some of my cities are founded late, when IZ's and buildings are already being built.
Unit numbers and composition depends. Usually I do a bunch of archers and one warrior for the first target, then add some horsemen for the next war, if I have 2 horses. I'd very rarely attack multiple cities.
When to have x cities depends. The sooner the better, of course, but there cannot be any hard rule. Building more cities when Industrial Zone buildings are up is fine. I usually do that as well, to fill in any empty spots near my spaceport city. With surrounding power plants the new cities are very fast to get up and running.
Also, the build order for districts and buildings, do you build the ones which finish sooner or prioritize production first? And also, a full IZ I take it means workshop + factory + powerplant?
Again, depends... Early on I usually go Factories before Libraries. I think Power Plant before University is also mostly the right way to go, as science is rarely the absolute bottleneck. You are correct on the full IZ.