I'd go more off your axle and tire ratings since it's a 2500 diesel, but that's just my opinion.
I also recommend considering a used unit if new prices are pinching you a bit. These things depreciate quickly and you can get a great deal on some of them if you're careful compared to buying new. We recently upgraded from a pop up to a fifth wheel and it's actually a great example.
First buyers bought it new for roughly $14,000, sold it to us 4 years later for $6500. Lost $7500 in 4 years.
We bought it for $6500, sold it 5 years later for $5500. Lost $1000 in 5 years.
The numbers will be bigger with a fifth wheel but the concept is the same.