1- I think it's great to be able to look at an old topic, don't see a downside to reading older stuff.
2- on this topic, one other factor to the bike+gear= less than half body weight general rule is how strong a rider is, legs, cardio and all that.
I'm a skinny guy who is probably very average in terms of power, but some big guys with big legs really do have the equivalent of big diesel engine power. I'm the opposite, but then again a big person who is overweight can also be out of shape a lot, so lots of factors going on here.
For me the half rule pretty much reflects what works for me.