I was a bit confused by the PDS limits in an introductory game. For multiplanet systems is the limit two per planet, or two per system (I was told the later)? If setting up in a multiplanet system, is it legal to put down four PDS in dual world systems, or even all six PDS if I take one of the triple planet systems from SE?

It is 2 per planets, so yes Hacan can have 6 PDS in their Home system, or you can get 6 of them in the Rigel or Ashtroth/Loki/Abaddon system.

Coupled with Deep Space Cannons, that can be an excellent way to defend your territory, too! (Though some don't like it because it could encourage turtling).

OTOH having a good defense grid like that with could encourage combat, since you'd be more able to send ships out to attack rather than keeping them in your own systems for local defense.

Nikas Zekeval said:

Nikas that sounds like how I would handle it. I may have to give that a shot in our next game (if I am lucky enough to end up with a multi-planet system.).