Hull E would be overkill. Also, the Orion doesn't appear to come equipped with cargo containers for the ore that would allow ship-to-ship cargo transfers.
</plan foiled>
It would be better to just have a standby defense team in-system while the team of Orions do their thing, fill up their hold, make sure the mining sites are bookmarked, head back to the station to offload the ore, then repeat the cycle of mining.
The Orion has an absurdly large cargo hold for ore anyway, it's pretty obvious that CIG intended this so we wouldn't need transport ships to move the ore.
So here's what my personal structure for a large TEST mining op would be:
Defense Team: 1 Idris-P, equipped with a minimum of two Gladius fighters (loaded up with heavy ammunition), one Gladiator, and one Hornet.
Alternative Defense Asset: 2 Hornets, at a minimum, would have to park near the Orions and power off some of their equipment to save fuel while keeping sensors on.
Mining Team: Minimum of 3 Orions.
Combat assets prepared in advance at the station or planetside, so that any nearby TESTies can respond by hurrying to the staged assets, jump in, and take off to defend our Orions.
The Idris-P would watch over the Orions at a safe distance, not too close to scare off the dumber pirates, but far enough to bait the small fry into attacking.
The Orion should be able to continue their work with minimal interruption while letting their automated turrets keep the enemy pirates at bay, as the Defense Team moves to engage with their fighters.
We don't really need a complicated structure for mining ops. Just get to the point where our advance scouts discovered the mineral deposits, get that ore, go to station, sell. Done.
Also, re. profit splits, that'll probably be a per-operation basis, we are unlikely to institute a fixed rate in TEST.