Dont overthink the compaction issue with these little tractors or any tractor for that matter. You will have compaction regardless of what you use whether it be hand tools and walking, mules or tractors. Some compaction is a good thing as it seals the dirt to prevent loss of moisture, ie packing wheel on planters. Yearly compaction is one of the reasons we do soil aeration with disc, tillers, plows, sub-soilers etc. As discussed, keep your tires in the middles and the planted row will be fluffy and you wont hurt a thing for your garden as the feeder roots dont extend to the middle. Fall tillage to turn under all the foliage will help keep the soil aerated also in addition to adding the organic matter back to the soil. Most plants only use the top 8" of soil at most so super deep subsoiling is not needed unless you are dryland farming and need to soak up some winter moisture. I have read that a human foot puts as much pressure on the soil as a tractor tire due to the small area and if you have ever had a foot stepped on by a cow, then you know how much pressure is put down on those hooves per sq inch for a 800 lb. animal. Total weight divided by contact area= pressure applied as compaction. Tractors with industrial tires compact less than Ag tires. Dozers compact the least due to such large area for the tracks even if you consider that they may weigh in excess of 50K lbs.