Well, that's about what I expected.
Nephilim ships in general are based on regular heptagons along their axis of motion; that's not that big of a surprise. So their weapons are arranged in rings as a rule, one weapon emplacement per side of the ship. Only exception to this rule I could see was on the Kraken, where with the aft batteries there were two guns along the ship's "underside", with no emplacement on the immediately adjacent facings (i.e. there were only six guns in that ring, as opposed to the seven up front).
I had the ships set neutral so they wouldn't shoot at me, but I'm going to assume that the guns have full range of motion. So, at this point I just need to sit down with my notes and a silhouette of each model (which I have, of course) to figure out arcs.
As far as the actual work went: when I got home I put Prophecy on my laptop and built the mission. Naturally, the damned thing wouldn't work on the laptop, but I figured I could try copying the mission file over to my Win7 machine. Damn thing worked then, so it was simply a matter of rebuilding the mission with a different Nephilim ship set each time on my laptop, then copying it over to my Win7 machine (overwriting the older versions as I went). Convoluted, but not as time-consuming as it might sound. And moreover it worked...
I'm fairly knee deep with Enyo at the moment, but I'm hoping to get these wrapped up very soon now.