At first glance, this raid is hard... and it is. But I have been able to play a little bit and completed 3 B sets so far, and have spent hardly anything, so I'll share a quick bit about what I've found on how to do the B set.
41, 42, 43, 45: I use the same strategy for all of these targets. I enter with a 2 ship fleet - 1 instant repair Seawolf and 1 Predator. The Predator is the 2 Havok 4, Engine 1 build all new players should use to open salvage. I have 4 fleets set up like that. I enter the target, and try to survive with the sub until one side or the other is dead. In the 42 it takes quite a few tries, but it is key to make sure all of those Reaver hulks are dead. In the 45 I've found sending the predator South works best, and usually it can get away on the second try. After that, I send in my Cat drive Spectre fleet, and take out the enemies. The 43 is trickiest, because the Reaver hulks with the long range cannon will damage your subs. I've repaired my subs to zombie levels usually, but on the 43 you'll need 1 coin of repair each to stand up to the fire when you surface. Stealthy Barracudas or Reapers may work here as well.
44: This target has Reaper subs and ECM Destroyers - I use a 4 ship Siege Missile SFB3 MCX fleet with 1 R5 Battlecruiser with Sonar as a spotter. Many of the Reapers can be seen at range, a few can't. The reapers don't usually stay under ECM cover, so those targets can be kept for last. Careful driving helps since the range of the torpedos is 78 vs 86 for my siege missiles. Targeting the stealthy reapers when they surface also helps to reduce damage. I take 35 - 60 minutes damage in this target, and can generally repair my fleet while doing the rest of the B set. I think Launcher or UAV-equipped vessels could also work here instead of the MCX (as long as you have a spotter) since you can damage visible underwater reapers... the longer range might make up for the lack of retargeting.
With no limit to the number of tier bonuses you can receive - hopefully these strategies will help you get what you want. I may try these strategies on the A set soon too... Good luck pirates!