The OP is intending to change oil every 3100 miles (5k km) in a 30 year old Toyota diesel. Honestly, as long as those km's aren't taking him years to accumulate, I think the topic is overblown. The majority of what he has to choose from is between 10-12 TBN; not a huge difference.
I would recommend he find the oil from his list that strikes a good balance between higher TBN, decent price and ease of availability. I seriously doubt he'll see a statistically significant difference in wear data between his choices with such short OCIs. If he were an OTR rig owner running really long OCIs, this topic might matter. At 3k miles, it's moot because none of the lubes are going to be anywhere near depleted of TBN and acid build up will not be overwhelming.
Get a few UOAs and find out what's going on to confirm.