OP, If you are not in a hurry, and want to get some real down to earth lessons in 5-tons, come to the Georgia Rally in October. There you can see 5-tons in all engine configurations, and most everythng smaller.
Yes even the LDS multi-fuel 5 tons, and some of them actually do run well, not as stout as the 250, but will maintain governed speed even with a significant towed load. Who knows you may even want to explore one the the GASOLINE powered trucks. They sound so cool................, between the gulps of fuel.