""150pilot""   yep, 3 axle road grader/scraper setup.   ya getting near to some of my thoughts....   while primary focus, has been physical width in the field, wider the better.    but there are other applications,  such as manure, either dry or liquid,  and it might be easier to just drive into field and drop some injectors / knives down into the ground on an 8 foot end and go or putting in field tile. 

for myself, though i have skipped wanting to place anything "under" the SSTT.  there is some physical limitations.  "wheels" needing to rotate 360 degrees. and with 8 foot width, even with 24" diameter wheels only leaves about 30 inches of space under the main frame. before there is interference with the wheels.   and going with slightly larger diameter wheels say 36 inch diameter wheels, and you just ate up all the room under the SSTT.      

i want to reduce compaction. and only way i am going to reduce compaction, is more tires and/or tracks. 

seeds, fertlizers, pesticides, chemicals, they all weight a good amount, fuel weighs, all the frame work, and fluids (oils, to coolant fluid) all adds up. to me i, need a way to say yes, you can add this extra weight, but also have abilty to reduce weight when it comes to compaction.