i've never done it as i don't have a tractor, let alone a second vehicle the size of said tractor to tow-bar it with.
however, that said, i've done too many accident investigations for me to say that tow-baring an equally-sized truck with a tractor is a good idea. there just isn't enough weight on the rears of the tow vehicle to keep the front of the towed vehicle tracking well. what's the front/rear weight bias - 75/25? 70/30?
the last incident investigation i was involved in was two 931s - the towed 931 spun the towing 931. this caused a jack-knife and rolled the towing 931 (injuring both soldiers). this was on paved roads and occurred when slowing as the truck ahead of the two slowed. speed was 35-40 mph. trucks were A2 models with the ABS mwo.
flat towing using a tractor isn't an art-form, it's a risk. i'm sure many people have done it successfully, but that doesn't mean that it is done safely.
just my
.