I am trying to determine the best average tire pressure to run in my tires on my 40' Marathon. I see different recommendations everywhere. My tires say run a max of 120 psi. I don't think I am maxed out with my weight, so I am currently running 105 in front, 110 on drive axles and 105 on tag. I see that some run 75 in tags. Is there an average setting for each of my axles that I can use that will cover most situations? Thanks.