I don't believe the maximum tire pressure is a good normal setting, that pressure is what's required to carry the maximum load the tire is rated for plus a little extra to allow for maximum reasonable temperature buildup. The pressure Honda recommends should be pretty close since there isn't all that much room for vastly different physical tire sizes on the bike so the volume of air in the tire doesn't vary all that much with brand. Since all the tires for this bike are bias ply, roughly the same size, the amount of air pressure to carry a given weight shouldn't vary greatly. That said, it's safer to err a little on the high side than the low side, so I'd go with the bike maker's recommendation and it it felt a little low, adding two or three psi isn't going to make a dangerous condition. You can also get a good idea by looking at the tire track, with a full load on is the tread mark on the ground looking too wide, on bias tires especially if they look too low they usually are. This wouldn't be true on the 1800 since they are radial.