Science & Industry

Well, your high sec defences are:

(1) Your force field
(2) The 24 hour war dec mechanic
(3) Strontium
(4) Your location

Basically, you don't need any defences at all.

I am wondering what you want a corp hangar array for?

Labs have 25,000 m3 of storage space, which is organized into tabs just like a corp hangar array. It may not seem like much compared to a CHA, but its is more than adequate for all the blueprints, data sheets, interfaces, decryptors, data cores, and whatever else you will ever need for research. Ditch the CHA, you may be able to put up another lab instead.

Some players will tell you it is best to never put BPOs in a POS anyway. Put up your POS in a system with a public station, keep your BPOs in the station, and with 1 level of scientific networking you can use your POS labs to research them. This keeps them safe even if your POS should ever go offline for some reason (like a wardec or simply not keeping up with it's fuel supply).

If you are not wardecced Concord protects your POS in highsec. If you do get wardecced, you can take the POS down, but this is more hassle than you may realize. Aside from gathering up all the stuctures and contents and taking them to a station, to reanchor your tower will require arranging that your corp have adequate standings with the faction that owns the system. Juggling corp membership and waiting through the 7 day standings recalculation timer is a major PITA.

Better, IMO, is to leave the POS up, but make it impractical to attack. Jammer batteries are your friend here, they will do far more to discourage an attacker than turrets. In highsec, no one can attack you with a capital ship, and jammers will shut down sub-capitals quite nicely. POS jammers are much more powerful than ship mounted ones. When a wardec comes along, offline a lab and use the CPU to online several jammers. Only an insanely dedicated corp, someone you have really, really pissed off, is going to take the trouble to attack a POS protected by jammers. They aren't likely to get anywhere unless they have several more ships available than your POS has online jammers, and they can't leave their shis bombarding you afk because the jammers switch targets and cause them to keep losing lock and having to retarget.

I have about the same setup, specifically for T2 production: 2 toons for invention and manufacturing, and 1 for copying and T1 components and rigs. My (large )POS setup has 3 Mobile Labs and 4 Adv Mobile Labs, as well as assembly arrays for ships, mods, and components.

You can definitely do good with a medium POS and fewer labs, but I wanted to be able to push out as much stuff as possible as quickly as possible, and at the same time have some defenses. You don't have to put up shield hardeners and ECM batteries, but doing so will make your lazy and cheap neighbors a much easier target to grief than you.

May i ask how you get the standings to get the pos in high sec?

Missions grind? Or corp?

On the corp hangar array thing, just go with a small ship assy array instead. More storage space, plus added bonus of being able to make T1 and Faction frigates and dessies in it. I stopped using corp hangar arrays a couple years ago.

It's really not that bad. According to IPH, a day's worth of production nets between 70m and 100m isk. That's with 18 production lines between two chars and setting the jobs to run once for the day. A large POS only costs about 16m a day to run. If all you did was log in once a day to set the jobs and lazily sell everything in Jita at the lowest prices, you could still net over 1.5b a month. If you put in more time and effort to keep your slots running, produce PI products for fuel and components, and sell items in regions with higher prices, you can easily be making 3 bil a month with three chars. And of course that's all profit.

The biggest thing is learning to use Isk Per Hour. Know what's good to sell and when and where to sell it. And like I said before, you can definitely get by with a medium POS. It's certainly not a bad idea now considering the cost of fuel being so high. The large can just be a better deterrent for griefers and provides more room for more labs and assembly arrays.

Edit:
I will say this about the work load: The most effort involved in a setup like this is inventing the T2 BPCs. If you're running 18 a day, then you need to be making at least 18 a day on average. That means you'll need to have the two inventing toons run at least two sets of 9 BPCs for invention every day, but assuming you're getting less than 50% success you'll probably end up doing three a day. I usually manage to run my invention slots at least twice a day for mods (which take about 1.25 hours), then set a few frigate BPCs (which take about 12.5 hours) up for invention before I go to bed. Then on the weekend when I have more time I might run 5 or 6 sets on each char.