Nobody asked so I will, what kind of soil do you have? I operate an MX track and the clay base gets packed really hard just from bikes riding on it. I don't think your tractor would pull a heavy enough disc. A rototiller is too slow and risks being damaged and the blades wear out fast especially if you have sand. A soil pulverizer isn't likely to get damaged but a good implement to look at would be horse arena groomer with the scarifier teeth. A box blade the teeth are too far apart and just leave grooves and they can be hard to pull in packed ground. The best time to groom is after a rain when there's moisture in the soil. If you get the soil worked up good and as deep as possible, groom it regularly or it will get hard packed and be hard to work. I've added sand and it still gets hard packed. I made a heavy harrow out of a 14" x 105lb/ft. H beam with backhoe teeth adapters so teeth are easy to replace. A drag implement with some kind of teeth will be much faster, easier to pull and less likely to get damaged. Ripper teeth like on box scraper try to dig deeper and take a lot more power. If you have a neighbor with a heavy disc, see if they could do the initial loosening for you. I used to groom my track every week and people complaining I should let it get rougher so I stopped grooming it as often but then it gets really hard packed. Look at some horse arena groomers with the scarifiers and adjustable wheels to get an idea what I think would work good for an MX track.
