After crafting from 57-67 rc through the abyss (thats over 38k natures, or over 1200 trips), I have not seen one pker under level 70. The problem with that, is you have to spend around 350gp per run, and it takes longer to run through your house and get to the glory, than it does to just have a glory in the first place. Most people want to maximise the amount of nats they can craft in an hour. Many people, like myself, even use energy pots while crafting.