I have had both 3/4 and 1 ton SRW trucks for towing fivers. My take is that if you plan on Towing a fiver greater than 10k lb (2000 lb pin) a 1 ton SRW is warranted. Anything over 14k lbs (2800 lb pin) a 1 ton DRW would be better suited. Keep in my mind I am basing this opinion on payload ratings only. There are many opinions on this topic, but I for one choose to stay in the comfort range of not exceeding GVWR, GVWR or GVWR of my tow vehicle.
I have towed overweight with a 3/4 ton and do not like the feeling of having too much trailer for a truck. I would never forgive myself if I got into an accident due to being overweight and hurting someone. I also like arriving at my camping destination feeling relaxed.