First attempt fail. Ground rules were: Do not build triangle-ships, transfer to Neinzul Enclaves Starships ASAP and build from them. If you want standard ships, you gotta steal them with Nanoswarms.
The problem was that I didn't adjust turret/FF numbers correctly going to 5-hw ultra-low cap, and forgot that certain exo-spawns were immune to Black Hole Generators (Money could be better spent on fortresses, perhaps). The first exo (golem+spirecraft) brought a couple of Hunter-Killers barging up one end through the BHG while a few raid starships sneaked through the other. The third front along the central route had been stopped, but that's probably because it had no Force-field-ignoring bastards invaders.
= = =
The AI settings were Radar Jammer and Counter Spy, respectively. They opened up with Parasites (Boo! Can't claim my Neizuls!), Laser Gatlings and Vorticular Cutlasses, then purchased Paralyzers (they stop turrets?!) and Armor Ships.
I thought I could claim a few Radar Jammer-IIs for my own use, but that also brought about some poor defense placements... The numbers look very funny compared to 1-HW/normal cap: although I got 50 FF-Is to play with, I actually need to place 5 down to give the equivalent defense of 1 FF-I in single player. On the other hand, Ultra-low caps reduce the number of turrets such that I got 75 basics. It's almost a scenario in which 5 giant forcefields are protecting 1 lonely turret and 5 grav turrets.
On second thought, what did me in was probably the bigger multi-tasking innate to 5-HW waves, since they can come from several extra directions. I could restart later, and, I don't know, simultaneously operate 5 independent carrier groups or something. It might be easier to maintain a balanced front.