Main target should be the small tonnage ships. The reason... SH5 has built in only huge ships with over 5k tons. So no wonder we have millions of tonnage sunk in just a month of patrol and this must be fixed. We need more merchants, but low tonnage merchants.. normal ships, not monsters.
I reduced the campaign mission requirements very much, instead of 200k, now we have max 50k tonnage, mostly 20. But with the sh5 fleet this requirement can be achieved in a single patrol. If we import low tonnage ships, the 20k requirements can be difficult to achieve. This way the whole campaign can be more realistic.
Here is a
small pack with ships extracted from Uekels mod, ships with low tonnage, but also with NOLNippon which is a huge and beautiful tanker. Not sure about this one as in reality tankers were a pretty rare sight and this one never sailed in Atlantic... but hey, I dont think anyone would mind sinking this fat lady :P