Oh mate, it's that sort of calculating loads over a series of steps that alientates people. The bottom line, and it's very easy to understand, is that it's easier and less tiring to walk with a lighter rucksack than a heavier one - it's self evident really, you don't need to justify it all with scientific evidence. Oh, your stride-length argument is flawed since you forgot to factor in the extra weight lifted over the additional number of shorter steps you'll have to take. If you were correct, you could simply take pigeon steps and the result would be near effortless progress. Erm, I don't think so...
The main factor with stride lenght in reality is that if you overstride on the flat, it's mechanically inefficient because you're actually braking slightly with every over-extended step. On the uphills over-striding is harder because you're having to lift more weight with every step, but that's generally true regardless of your pack weight, on downhillsit's conversely the case that understriding is often harder because you're braking and using muscle power to stop momentum whereas in reality you should try to utilise that forward motion. It's discussions like this etc...
Anyway, it's true, obsessive lightweight packers are weird and cult like. The point I was trying to make is that you can save weight without being some sort of fanatic.
