Go ahead and roll the opposed haggle tests, definately, using a skill rating of 40.<br/><br/>As for giving Ares proper ICBM coverage, 16 missile silos should be sufficient.  Each shield protects one planetary facility, and shield generators overlap instead of stack.  (that is, if you have 3 small shield generators wired together, they protect the area with one void shield over a 15 kilometer area, rather than protect a 5 kilometer area with 3 void shields.  It isn't neccisary or advisable to protect the entire surface of the planet, and each shield generator can be assumed to protect a single installation or military unit, though more can be gathered under the heavier shield generators.<br/><br/>You can place several defenses or military units underneath a standard shield generator, but they'll likely all be vunlurable to a single orbital bombardment, meaning that if your enemy has sufficient weapons to get past your shields, you'll risk losing the entire facility.<br/><br/>Also, shield generators are useless against ground assaults, though they mean that any bombers have to get into heavy bolter range to drop their payload, instead of simply nuking the enemy from high orbit.  Naturally, most ground assaults have a primary objective of knocking out shield generators and orbital defenses so that naval assets can wipe out the enemy with orbital bombardments.  (a tactial bombardment is still possible through 1 void shield, of course, but needing to get at least 2 degrees of success with a -40 to -60 penalty already on your roll is pretty risky, especially when there's probably torpedoes being flung at you and massive swarms aeronautica launching anti-ship missiles to take you down.)<br/><br/>As for orbital defenses, defense platforms are assumed to be able to maneuver somewhat, and have weapons located on every firing angle, so they don't leave blind spots within their range.  Imperial planners consider 2 defense platforms  sufficient for most planets below a certain tithe grade, though forge worlds and hive worlds usually have 4-6, and capital worlds, and fortress worlds tend to have 8-12.  The range of the weapons is the only consideration in building your defense web, so if you bought range 6 weapons, placing 4 platforms 6 VU away from the planet, and 8 platforms 6 VU away from your core defensive line would probably be optimal.  A more spread out defense is another option, designed to wear down ships before they arrive, rather than try to repel them with a brittle line of defenses.<br/><br/><br/><br/>