The Face of the Enemy (Destroy this Ship!)

[Nitram Draw]

PPB's have a short range. Try to build some ships with Wave Motion Guns as stay at max range. Another possibility is Null Space weapons, skips shields and armor.
I'm not real familiar with the crystal weapons but IIRC crystal armor adds to shields so load up on that armor to keep you defenses strong. Fighters could also help espescially heavily shielded fighters with 1-2 weapons. 5 PD's per ship is not that much if you can field 1000's of fighters that require more than 1 hit to destroy.
Good luck man, sounds like you are in for a long fight!