It's official; Team 3 is dead. I've completed my conquest of the Emerald cluster and have picked up a couple former Amethyst worlds in the bargain. I even managed to salvage photon torpedoes and another couple of techs to boot, though I'm now morally confident that AM Warheads and Neutronium Ammo can't be salvaged at all. Instead I've gotten picks from the Biology and Industry trees. The latter is probably Quark armour; I'm not sure about the former but it might be Grav Adaptation. Both of those will probably take quite some time to figure out what they are, before I can actually research anything.
In the Emerald cluster, all that's left to do now is defend it against various waves of gate fleets headed my way. So far my fission-era forces have enough combat power to do the job, so long as there's no CnC, but I've found I need to add some fusion-era ships anyway. My fission fleets just aren't fast enough in tactical to catch AM-era gate ships or other fleeing non-combat vessels, and I can't afford to let fights drag out over multiple turns, as in some cases I have multiple fleets arriving on successive turns from different Team 2 empires.
Of course the bulk of my fusion-powered navy is focused on defending my holdings in the Amethyst cluster and preparing to take the fight to Team 3. To that end I've finished researching Armada CnC and forming my forces into four Armadas, with more under construction. These are cruiser-centric Armadas with just the CnC as a dreadnought. Mostly they are armed with AP drivers, heavy AP drivers, and disruptor torpedoes; there are also a few EMP torps and heavy combat lasers in the mix. While my initial four armadas are largely ready for action, they still could do with a bit more fleshing out so that I have deeper reserves; I'm currently targeting 16-18 combat cruisers per armada and am not quite there yet. I've just finished researching Heavy Fusion Cannon, so that is going on some of the new construction to see if I prefer that in place of heavy AP drivers. Since I don't have Neutronium Ammo, I expect I probably will prefer HFC, but that needs testing.
I've focused more on cruisers than dreadnoughts for a couple reasons. The biggest is simply that they have far better price points, particularily with respect to upfront cost. Also, and importantly, I don't give up a lot of firepower by sticking with cruisers over dreadnoughts; 3 basic cruisers are much more comparable in terms of firepower to one basic dreadnought than 3 destroyers are to a cruiser. In fact, I can actually field more heavy guns on the cruisers, albeit with some loss of secondary armament, and cruisers are better for maintaining an outnumbering bonus. I still have destroyers in my armadas, in a PD role, for similar reasons; I considered adding some spinal mount AP heavy driver destroyers as well, for cases where PD isn't as useful, but so far haven't needed to.
The upside of dreadnought-centric fleets, as compared with cruiser-centric ones, is that they are less brittle. Each DN can take considerably more punishment than 3 cruisers -- in fact it's more like 5 or 6 -- without getting knocked around as much. You also don't need to be as careful with your Armada CnC if you have other DNs to act as linebackers, than you might have to be with only a cruiser screen. However, wounded DNs are a lot more challenging to extract from a heavy firefight than wounded cruisers, and are a lot more expensive to replace if you fail, or to field in depth to begin with. And deep cruiser reserves can in some ways partially mimic that extra toughness you get from DNs, especially if you have access to advanced metal armour. With my target of 16-18 combat CAs per armada, I have about the same firepower and effective health as 3 combat DNs, or better, but at about 2/3 the price and with more flexibility. On the whole, at the start of the DN era, I think the choice of DN-based vs. CA-based armadas typically falls out in favour of the CAs, unless your opponenents' forces are such that use of DNs for their size, mass, and toughness is critical to making the matchup come out in your favour, or unless your economy has ceased to be a limiting factor.
I can't afford to let my beachhead in Amethyst get seriously threatened, so two of my armadas are guarding Winath against potential farcaster attack. Besides, I don't yet have a lot of routes bored through this cluster, and moving multiple armadas around degrades nodelines quickly. The few routes that I do have are mostly to well-defended worlds, down long nodelines I can't traverse in a single turn, such that surprise is out of the question. But I can't win this game solely by defending my turf and glaring across the border. Since my armadas are designed to be relatively affordable, I decided to risk one of them on a 2-turn attack at Kop're'ke, a former Amethyst colony which looked to be guarded by a small Diamond armada, but not much from the other factions. Fortunately, Team 3 did not reinforce, so I was able to pit my cruiser armada against 2 Diamond CnC DNs and a Support DN. Encouragingly, we came out on top handily, so now Kop're'ke is a new and swiftly growing colony of our own.
Nevertheless, I still feel like I ought to treat these cruiser armadas with a certain amount of care. While I think my armadas can generally tackle a single enemy armada at a time and not come off too much the worse for wear, they will probably fold quickly if the fighting gets too intense, e.g. because of a bad matchup, or fighting more than one enemy armada at once, or insufficient depth of reserves. Diamond in particular has the tools available to really ruin a cruiser armada's day, if they start fielding solid designs in well-formed fleets. I'll have to be careful how much risk I embrace in pushing forward with these CA armadas, and a switch to DN armadas may eventually prove necessary.