Hi range, 3rd or maybe 2nd. 3rd will be pretty fast once it starts, but will pull easier than 2nd.
Does it have brakes or do you have to use the 12 foot brake under the middle? If the 12 footer, have it close to the ground, couple inches is not too close on level surfaces, so you can stop quickly.
D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time😄