Randy, head to the scales and get weighted. Although weights for each tire would be nice, I think its an overkill.
Weight for each axle is ok, (front and rear). Then use the table that comes from your tire manufacture. It will give the minimum pressure for each tire when used as a single or dual configuration.
My placard from Coachman says to run 100psi in each tire, after weighing, the tire manufacture says the minimum I could run is 70 psi.
2001 Coachmen Mirada (Ford F53 6.8L V10) - Toad 2001 Civic
It won't do MACH 2, but I can get a sandwich and take a pee.