I'm hardly knowledgeable on scrapers, but I have a 135hp Kubota with Ashland's 5 yard pan. Weight and good ground is indeed your friend, my tractor with the empty loader bucket weighs 17200lbs and it pulls the pan well (in my inexperienced opinion). I load the front bucket for more weight when running my scraper.
Your cut is 15.5" wider than mine, double the weight and double the power roughly. Your scraper weighs triple mine. In good ground (big caveat) I would think your tractor would do well enough.
That being said, my setup is for personal use, I wouldn't consider running it hourly given the hourly rate, what it cost, and my overhead. I might would entertain bidded work or by the yard, but it's fairly well down the list of my prostpective income.