Ideally you find the Load Inflation Table for that tire from General or find it on the net. Then you know exactly what General says is safe for what weight at what PSI. I have used them before for other brands never ran a General so cant point you to it.
The vehicle placard is set to the psi for the OEM tire that corresponds to the vehicles max weight rating as they (the government) knows in general that most drivers are not good about checking tire pressures much less getting weighed and adjusting their pressures appropriately (if you look up the OEM TPMS specs/rules/laws for vehicles it pretty much comes right out and says that). If you weigh your vehicle and you get your actual weight or weights ie normal weight, loaded weight you have your upper and lower limit. My truck fronts are at 65 and rears 55 (I could actually run lower on the rears) unloaded, loaded I run 70 front and 65 rear based on my weights
Here is an example of what I am talking about again it is not the correct one for your brand/tire but is just an example but General should have one
https://toyotires-1524598101.netdna-ssl.com/media/2125/application_of_load_inflation_tables_20170203.pdf
2016 Jayco 28.5 RLTS