I’d research how to easily tell gear ratio. But I suspect the RPO codes are indicative.
Regarding a wdh, you are thinking like most non travel trailer haulers who don’t automatically believe a wdh is required. And having had an auto ride tahoe, I can say the system is not overly robust for payload. Therefore if it will pick up and carry your tongue weight without issue, then it’s close to or within reasonable payload.
Our 01 tahoe we had last year briefly would pick up the tongue weight of our 32’ v nose sled trailer. But the tongue was not heavily loaded. Only had 3 machines in it and they were placed back a bit for cog.