Economics and quick unit building

For this topic, my goal was to find some simple economics to guide base building, with the idea that ultimately we want to produce units as quickly as we can. I'm intending to explore this further than just this OP, but I wouldn't mind some help.

In your starting area you have four metal deposits. Extractors provide 1 metal per second (mps), plus you get one just from your seed. A factory continuously producing T1 units consumes 5 mps, assuming you do not get engineers to help, which means your starting base can continuously support one factory. In real gameplay it is actually less than this, because you need to build logistics buildings too. Without capturing additional areas, you can get 3 logistics buildings, for a total of 40 logistics. Each T1 squad takes 1 logistics and each engineer 3. I have tended to start with 2 engineers, leaving 34 logistics for units. 102 T1 units is a pretty sizeable army, and it only takes about 7.5 minutes to get there.

Once you start to expand you get more power, thus can support more buildings (factories and logistics, mainly). Typical resource sectors provide 3 metal or 3 reactives deposits. You need a minimum of 5F - 1 metal extractors to continuously build units, where F is the number of factories (the -1 is the seed). Again, you have to allow more than that in order to allow for building logistics.

Let's say you have some reactives coming in. You'll probably want to start building battle groups. To achieve full battlegroups and continuously produce them, you need 1 T2 unit and 5 T1 squads. These can be built by two factories in 36 seconds, using a total of 390 metal and 10 reactives. Thus you need 10 metal extractors and 1 reactives extractor, again not factoring logistics.

In the quick start map, you don't get much more resource nodes than this close to your base, so you are unlikely to want more than 2 factories at a time until much later in the game. More than the 2 factories and you have wasted metal constructing them. The only reason to build more is to have factories closer to the front lines, very valuable certainly. But even so you'd probably have to keep your base factories idle. You also need to account for the building of other structures, which takes metal and reactives away from war units.

If you want to boost factories with engineers, you can do so with diminishing returns. A T1 squad takes 12 seconds to produce normally, but only 8 with 1 engineer helping. That's a huge bump. Keep in mind while you are producing units faster, you are also consuming metal faster, so you'd need the extra extractors to keep up. If you don't have sufficient extraction you will eventually run out of metal, and at that point you will not gain any extra speed from the engineer. With the help of 2 engineers, units come out in about 6.75 seconds.

I also looked into the refineries. The first metal refinery costs 600 metal, 120 reactives and gives you an additional flat 0.5 mps once constructed. It therefore takes 1200 seconds (20 minutes) to recoup the metal spent, not including the metal used to research the needed tech or the reactives spent in the research and construction which are not recouped. The reactives refinery gives you 0.1 reactives per second (rps), and costs 120 reactives, so it will also take 20 minutes to recoup the reactives cost (not to mention the metal which you don't recoup). The second refineries are worse, providing an additional 0.3 mps/rps, thus the cost to recoup those resources takes even longer. Furthermore, these refineries take 15 power, i.e. 1.5 sectors worth of power, each. In summary, refineries are either too expensive, too inefficient, or both. In addition to reducing their cost and increasing their efficiency, it might be valuable to have the refinery bonus scale with the number of operational extractors. Another interesting possibility would be for refineries to convert from metal to reactives and vice versa, with some inefficiency penalty.

So all of the above helps us consider game pacing. First, continuous production is definitely limited by metal extracting in the early game. I believe that is appropriate because it forces you to make a tactical decision whether to grow your army rapidly, or grow your base rapidly or somewhere in between. I believe the tactical choices are going to become even more pronounced when more air units and possibly more structures come into the game.

Second, let's consider the unit production speed versus battle speed. Put two opposing factories constantly producing only T1 units head to head to clash somewhere between them. The units take so long to destroy each other that each side gets the next batch of reinforcements long before the mini-battle is over. The result is that both sides continuously build up their side. So at this pace, a winning strategy practically necessitates, if you are able to produce T1 units continuously, you should do it and send them in a continuous stream toward the enemy. If the enemy doesn't do the same, they will get overwhelmed and lose. NOTE: This does not factor in turrets, I haven't tested that yet.