Hello everyone,
I have researched all about truck towing and am wondering what everyone considers the safe "buffer zone" to be under the max limit of the truck towing capacity?
I would really like to stick to SRW but is this enough of a buffer with these specs or should I invest in a dually configuration?

The truck I am interested in purchasing is this:
2020 F350 SRW 4x4 Crew Cab, 176" wheelbase, 20" wheels, 8' box, 6.7L Power Stroke V8 Diesel axle ratio 3.55, 10 speed automatic
Curb Weight: 7,397 lbs
GVWR: 12,400 lbs
GCWR: 30,000 lbs
Payload: 4,561 lbs (actual sticker on door of truck)
Max Trailer: 20,000 lbs

The trailer that I will be pulling is this:
2018 Sanibel Model #3651

UVW: 13,323 lbs
GVWR: 16,668 lbs

Im not sure about the hitch it came with but ballpark guess is approx 200lbs.
As far as additional payload = mysel + fiance, +3 dogs + gear = approx 700 lbs

Is this a big enough truck to safely haul this RV full time or should I look into a dually setup?
I hope I did the calculations right!

Hope to hear your replies and suggestions PLEASE!