Roger,
I read some of the info at the "Tireman9" website and want to add one comment regarding a discussion I read there about the importance/meaning of a tire's Load Range.
It's true what was said about a tire of a given Load Range at any given pressure not being able to (safely) carry any more load than a tire of lower Load Range at the same given pressure.
However, nothing was said of the other reason to go to a higher Load Range - not related to load carrying ability. That reason is tire ruggedness and reliability. Going to a higher Load Range gives one stronger construction (so as to withstand new higher pressures by design), but if you stay at the old pressure with the higher Load Range - you get improved failure-proofness at any rated pressure.
For example, we take our Class C MH off paved surfaces a lot and it's Load Range E tires at the pressures I use are under-loaded based on the weight they're carrying. However, I'd love to move up to Load Range G tires (but at the same pressures) to get more material in the tire sidewalls and tread.
Unfortunately it's difficult and expensive to do this because tire and rim manufacturers don't commonly make the needed combinations available for going up in Load Range purely to gain tire ruggedness. For example, I would like to keep my stock 16 inch rims - rated for a max of only 80 lbs. - but put Load Range G tires on them instead and run the Load Range G tires at no more than the 80 lbs. that the rims are rated for. This combination is pretty much a very difficult to find no-go.
I've used upgraded Load Ranges (but not at higher pressures) on my various pickup's tires for years, if I could get them, with outstanding longevity and no blow-outs. You see very little in the literature about going up in Load Range, but not pressure, for improved tire performance.