Bob & brholt, Thanks for the examples and your real world numbers. It sounds like you need a 1 ton DRW truck for all but the lightest of TCs if you want to be under GVWR. Based on your numbers I think you may need to add 1500# or more to dry weight get a good guess on what truck you will need.
It's a lot better to be a little scared of numbers than to buy a truck and TC and be scared driving down the highway.
I'm not surprised that a DRW is more stable, but I assume it is worse in the snow than a SRW. Or, does it not matter much when you weight 8000#?
Thanks again.