Tyre pressures?

HarleyDave

I don't have a service book to use as reference for my 2 berth Lunar Ultima 400(Lexon)caravan and am not sure what the tyre pressures should be.I recall seeing a formula for calculating pressures but can't find it.Info I have is:-MTPLM=1150.MRO=950.Tyres are 185R/14C Kenda radials.Have been given 2 different figures by dealer with a difference of 17psi,have been using 60psi but told this was too high by a friend that has more caravan knowledge than me