T2 Cruise Missiles -- Do I Need Multiple T2 Rigors?

I've been wanting to increase my DPS on L4 security missions.  I currently use an Armageddon outfitted with cruise missiles and sentry drones.  On a typical L4 mission, I have my sentry drones take out the smaller stuff while I keep the cruise missiles targeted almost exclusively on battleships.  Usually, my cruise missiles are still pecking away at the battleships after my sentries have cleared the field of everything else.  And on occasion, I have to either skip a battleship or switch my sentries to the same battleship my cruise missiles are firing upon before the smaller stuff is cleared, as I occasionally run into NPC battleships that can restore armor or shields as fast as I can apply damage with the cruise missiles.

I need to keep the cruise missiles focused on larger targets to ensure they can apply their max damage due to how missile damage is applied.  To apply max damage with a missile, the explosion radius for that missile needs to be less than or equal to the signature radius of the target.  I could work on increasing drone damage further, but then what do I do with my cruise missiles that can barely break some NPC battleship tanks?  I could focus cruise missiles on mid size ships leaving only battleships at the end, and then focus fire of the drones and missiles together on all the battleships. But what I really want is more cruise missile DPS to take down those battleships better.

There are skills I can train higher to improve missile damage further.  That's part of the plan, but I also want to consider T2 launchers and missiles.  T2 cruise missiles come in two flavors -- precision and fury.  Precision are for small targets and fury are for large targets.  Given my situation, I'm not terribly interested in the precision missiles, but I'm very interested in the fury missiles to take down those battleships.  So I will stay focused on that for now.

The main issue with a T2 fury cruise missile is that it has a huge explosion radius of 567 m.  Since I want to increase my missile DPS as much as possible, I need to make sure that max damage will be applied against NPC battleships.  To do this, I need to make sure the explosion radius is less than or equal to the NPC signature radius.  Now, I've read some threads that talk about going to what I would consider extreme measures to do this, but I don't think that's the right approach.  If you overdo it, you may be using modules far more expensive than they need to be or unnecessarily using fitting slots that could have been used for something else.  We need to look at precisely what is needed for the situation without going much further.

I researched a number of NPC battleships, and the low end of NPC battleship signature radius appears to be about 340 m.  So my target is to either raise that signature radius and/or lower the explosion radius until they are close to equal.  Do I really need 2 T2 Rigor rigs and 1 T1 Rigor rig to do this, as was suggested in one thread I read?  I don't think so.  Lets look at the ways we can change either the signature radius or the explosion radius:

1. Target Painters -- these increase the signature radius of the target by up to 30%.
2. Guided Missile Precision skill -- this decreases the explosion radius by 5% per level.
3. Rigor rigs -- these decrease the explosion radius by 15% for T1 rigs to 20% for T2 rigs.

Now, I'm not entirely certain how the percentages are applied (e.g. do they all add directly, or are they applied more like multiple resist mods), so I am making a few assumptions in my calculations.   In my case, I really don't have anything I am willing to switch out for a target painter, so I am going to ignore those for now, even though they are quite nice.  And then I'm going to see what we can do without going crazy.

With target painters out of my plan, that means I need to reduce the explosion radius by about 40%.  That's (567 - 340) / 567.  To keep things reasonable, I'm not going to suggest pushing Guided Missile Precision to 5, but we do have a ways to go, so lets say push it to 4.  That's a 20% reduction.  A single T1 Rigor rig is an easy fit.  That's another 15%.  If they add directly, we are already at 35%, or roughly 32% if they stack more like resists.  That's already enough for a large number of NPC battleships.  If we want to push it down all the way to the target 40% reduction, which may not even be worthwhile, we can either switch out the T1 rig for a T2 rig, train the skill up to 5, or maybe use 2 T1 rigs and not worry about training the skill up past 3.

The whole point of this exercise is this -- if you want to really optimize your fit, consider your needs carefully, and if needed, do the math to figure it out.  Do I need 2 T2 Rigors, maybe also a T1 Rigor, and maxed GMP skill?  No!  As I determined above, that is major overkill considering I only want to use T2 cruise missiles against the battleships.  I can get by just fine with a single Rigor rig and GMP skill at 4.