I think you have answered your own question. RSRD as you know makes targets much less common and supposedly more historical so you are going to have deal with the much lower amount of ships that RSRD spawns or not use it. I stick with TMO and dropped RSRD a while back myself. I need to have something to do out there.

I just go with TMO and if I get overly deadly in one career I will just start another one. TMO make the ships more rare than stock but not as rare as RSRD makes them.Not saying RSRD is bad its just not for me.RSRD uses "real" convoy dates so if you find this data I guess youd do ok but to me since we supposed to be a skipper during WWII wed not have that data would we?

Only ultra data at best.