No personal experience but a friend has used the same size trailer for his ITA car for about 15 years. Of course it's a short car, think Mk I MR/2.
With the car just inside the trailer he has about 3 ft in front. Enough for a work bench the width of the trailer with room for stuff below and above and tire racks on the side walls above the car. It works for him but may not for every racer.