fluid type for A-518

From my understanding the +4 will bring soft slippery like shifts, but i am getting a shift kit installed as soon as i get the time to do it or the money to pay somebody to do it.
I have just got so many zig zagged results when trying to find an answer to this question, i have done alot of searching online and found out that dtt an aftermarket company who builds transmissions to handle huge torque from diesels they reccomend nothing but dexronIII in the A-518, i have read online where people say dexronVI is the best to use, and of course those who say amsoil and royal purple and those who say +4.
This transmission the A-518 seems to have many different opinions as far as fluid. which kinda tells me they will run on anything kinda like the 3 speed 727, heck i even read some diesel guys are running tractor fluid and hydraulic fluid lol so trying to pick a fluid for this transmission is tuff, +4 is what dodge says, dexronIII is what big time builders say, never heard much talk on type f tho, i have read a total of 3 people running type f in the A-518 and they said they have no problems????? just confusing, you'd think everyone would have found out what works best by now and that it would be common knowledge but aparently not cause all sorts of people run all sorts of different fluids in this transmission.