After going nuts with coolant research, I have come to the conclusion that this stuff FAQ - Final Charge | PEAKhd.com
is the best stuff to get, in particular for my 1997 DT466 engine.
It is an OAT type heavy duty ELC without nitrite and (most importantly) compatible with silicon seals. It also meets the Cat EC-1 guidelines.
The key which makes it 'the best' is that it is rather foolproof with not requiring any additives or test strips, supposedly providing superior protection to the green stuff with SCA, being easier on the water pump and cooling components, and lasting 6 years.
There are other brands I ran into with similar specs, all good, but the Peak stuff had more straightforward information on what was going on. I also ran into many which were decidedly NOT compatible with silicon seals due to use of the cheaper ethyl-hexanoic acid.
I have also learned that Zerex G05 is not probably not a good idea for this engine, despite what I had initially thought.
This said, the 'basic green stuff' with proper SCA additive and upkeep will run fine too. The engines were designed for it, after all. This is basically a 'what is best for me' choice.