I have been playing SEIV with the TDM mod for some time.  In that version my early game research priorities are to get CSM-II, DUC-III, and PDC-III. I then create a small weapon platform that has 1 missile, 2 DUCs on large mounts and 2 PDCs.  This allows you to tag threats at 10 squares with CSM and then 8 with the DUCs which gives at least 1 and usually 2 firing opportunities before the attacker can respond.  Building a handful of these on a planet makes it pretty safe from most early game threats, especially using tactical.
So, I followed the same strategy last night with the SE-V demo and got completely glassed by 4 frigates with 3 DUC-II each against 5 of my WPs.  I did add combat sensors to the platform. First, large mounts do not appear to give a range benefit over a standard mount.  Second, to hit modifiers seem to strongly favor the attacker in this case.  The 5 CSMs that got away all hit one FG and then the remaining 3 FGs destroyed the WPs.  End result was one glassed planet vs. 1 dead enemy FG,1 badly damaged and 2 fully intact. 
 
Need a new strategy.  The FGs did not have PDCs, so I will go with an all CSM platform and see what happens.  Two good notes is that a small WP can be built on any planet in 1 turn as opposed 2 in SEIV and cargo space on domed worlds seems to be way up.  Any comments on what works are more than welcome.
Also note, the computer attacked with 4 FGs on turn 30 because I built a colony in his space (after a few warnings).  This was followed by another attack of 5 FGs on a different colony with similar results 2 turns later.  All that from the peace loving Abbidon Enclave.  I guess the AI is not so bad as in stock SEIV.
TM