The T25 is 50 inches wide. In a perfect scenario, you could find a tiller than was just a bit wider.
Your PTO HP is 18.3. Especially if your ground is hard or dense, you want to stay under that.
Very few tillers wider than 48" are designed for under 20 PTO HP.
There are a few that are smaller and offset, so you can till over your tire track on one side. Or just go with a 48" unit and you will have a few inches that the tires will compress. Be sure to look closely. Some will say 48" and mean working width. Others will mean total width.