more militaristic stuff
I already see that is where the big money is
Yes. If you look at some of the battle reports people have posted where they occupy a base, you'll see people sometimes getting 700-1000 credits all in one lump sum. In some cases, with only a single attacking ship. Later on there will be more money to be made from destroying fleets, but right now base occupations can be extremely lucrative.
If I upgrade my account for, say, a month, and end up having more than the 9 free bases, do I keep the additional bases
Yes. You
do keep them. Additionally, you
also keep any advanced structures you build beyond the allowable limit for free accounts.
Looks like I'll need some carrier tech so I can have a massive missile-killing strike force of fighters.
Yes, there are lots of bases right now that can easily be taken with a carrier-load of fighters. Try to get there soon though, as it will become more difficult once people start using shielded turrets, and over the next few days that will be an increasing percentage of people.
I'd really like a nice production astro. I'm guessing that
would be something with great solar energy and great metal.
Three metal, yes. Four solar is nice, but not completely necessary. With a little more tech you'll get access to energy generation buildings that generate 4 or 10 energy regardless of astro stats. They're just more expensive to build, so it's cheaper and faster with 4 solar.
However, I think you will find that "a" production base is not enough. As the game progresses, if you don't build sufficient infrastructure there will come a point where it's very easy to bring in far more money than you can possibly spend. Having only one or two prodiction bases, while having others dedicated solely to generating income is exactly the way to get stuck. All buildings that improve your production rates also generate income. So by simply building production buildings you get both income and production capacity. Whereas if you focus only on income, you tend to have lots of money and way way to spend it.
I recommend that you make
every base a production base. Even your research bases should have shipyards, factories and refineries just as high as everywhere else.
Note that if you'l be active in combat, this is even
more important, because of the extra income from pillage and salvage. A months from now you may find youself collecting tens of thousands of credits of debris after a battle. If your production capacity is no greater than your base income, it's difficult to spend those extra credits.
Battles are irregular, so income will be irregular. Plan to have an infrastructure capable of huge spikes of production.