Buying Class C Is Chevy 6.0 good for towing?

I've been towing with a Express Van with the 6.0 and 4 speed trans for 8? years.
First camper 5,500 lbs and I now have an 20ft Toy hauler - 4,500 lbs, with a
motorcycle in the van and about 300lbs of stuff;

I just did a 5,000 mile trip out to Big Bend and back so flat roads and hills.

The 6.0L did great - lots of torque; Cruised at 60-65 mph and got 11.8 mpg;
For the most part the trans was locked in top gear doing 2,100 rpm, trans
steps down on hills to 2,600 rpm;

The 6 speed tows better and the change down is not so great.

I have a 08 6.0 pickup, a 6.0 would be slow, pulling any kind of trailer you would be slower. I use mine for small short loads works fine for me.

How much does the trailer weigh? What’s the tongue weight? What are the C’s numbers?