Do covert op ship sensor types have any effect on the sites they can scan down

I think determining the ISK viability of a POS will have to come down to you having to do some rough math on your own. The price of fuel can vary from place to place and from day to day. Not to mention, the amount of fuel you will need can vary depending on the size of the POS that you decide to deploy. Then you also have the variable of how much you can actually sell your BPCs for. Some BPCs sell for more than others, but again there's a lot of variables to work in there, and it's hard to track a base price for BPCs since they sell through contracts. In the end, I think you'll have to perform the profit calculations on your own.

In regards to your second question, I can say that there's a good chance you could get wardec'd by a PVP corp/alliance if your POS looks like an easy target. My alliance has dec'd small corps in the past solely to try to crack their POS, and we have several friends who do it as well. It's less a griefer thing and more about trying to make an easy profit.

That said, there are a few things you can do to make yourself a not so easy target. For one, try to set up your POS in a less well traveled part of space. Jita and Amarr are the two largest trade hubs in the game, so you'd probably be better off not setting up shop in Domain or The Forge regions. When you do chose a system to set up shop in, chose one that's off any major travel routes. For instance, don't pick a system that's on the route between any of the four major trade hubs of Jita, Amarr, Rens, and Dodixie. You can research a potential anchor system with Dotlan. Click the Statistics link for any system to see graphs detailing jumps, player kills, NPC kills, and pod kills. The less activity on those graphs, the less busy the system is, and probably the better chance you will have of not attracting anybody's attention.

Second, how you decide to configure your POS will make a difference in how attractive it looks to a potential aggressor. There are plenty of POS configuration guides listed online, so I won't bother repeating their info here. Instead, there are just a few tips that you should know. First, spread your defense modules around. The most common layout is groupings at the top, bottom, and four along the sides. To make things even more difficult, don't place your defense modules in groups at all, but instead spread them randomly around your POS bubble. Sieging POS's set up like this is a huge PITA as your fleet is constantly on the move to hit the next module. Going heavy on the ECM can turn away potential aggressors as well. It can disrupt a logistics wing's cap chains, and it can be an annoyance for the combat ships, constantly having to relock the current primary. Also remember that artillery will still fire even if the POS has been reinforced. You shouldn't rely on it as your sole gun type, but arty can be a headache for a fleet. Lastly, take the number of defense modules you think you'll need, and triple that number. Do the same for your resists as well. And anchor all of it. You don't have to online all of it. In fact, you won't be able to. But nobody wants to siege a POS in high sec if they think they'll have to spend hours shooting down 80 POS modules as well.

Lastly, the most important thing you can do is to make friends. With the upcoming changes to wardecs you, as the aggressed party, will be able to invite friendly PVP corps into the war free of charge to them. It will be quite a nasty surprise to the aggressing corp to suddenly find themselves fighting 100 pilots instead of 1 pilot. Having good reliable friends in EVE can mean the difference between keeping your POS and losing your POS.

T3 Boosting alts are very difficult to scan down. The T3 boats already have a reasonably small signature, but as well as that they often fit ECCM mods which make the scanning signature even harder to scan.

In saying that though, it is possible. In a recent patch (6 months or so ago I think?), they changed these fits to not be unscannable anymore. It still takes a long time to narrow it down though, as you have to usually scan right down to .25AU on the probe radius to get a %100 hit. Where someone is "soloing" and only uncloaking/boosting while they are actually fighting, then you usually only have a limited window, as these fights don't last very long. I guess you're sorta hoping for someone to leave their boosting alt uncloaked, and not watching directional scan. You're also a little bit more likely to be able to scan these down if they are in a bigger fleet fight, which tend to last a lot longer.

Some of these fits are very pimped, and can only be scanned down with :

• a perfectly skilled scanning character. Just the skill names start with Astrometric, plus the Covert Ops ship skill.

• using scanning implants. There is a set called Low Grade Virtue, which is expensive but helps a lot, these go in slots 1 - 5. There are other implants with "prospector" in the name which help too, which go in slots 6, 7 and 8. On the plus side, even though the implants are expensive, the scanning character will usually be very difficult to kill if he stays in a covert ops boat.

• using a covert ops frigate, fitted with two Gravity Capacitor rigs, Sisters Expanded Probe Launcher (or the Tech 2 version), and using the Sisters Combat Probes.

Check out the eve online wiki page http://wiki.eveonline.com/en/wiki/Probing for the full names of skills and implants that will help.

The other thing that having combat scanning probes out will often do is cause the character to cloak the boosting alt back up again, losing them their link bonuses. While it won't net you a ridiculously sweet killmail, just stopping their boost alt from boosting can help a lot in some cases. Sometimes this may be the far easier thing to accomplish. A skilled player with a boosting character will often watch to make sure they only cloak when the scanning probes are closing in. Not everyone who can afford a boosting alt is a skilled player though... :)