I was looking up rigging forces as it pertains to log weight, and saw mention of a weight chart in the back of the safety manual. While I was looking at that, I noticed the pruning guide also. They're a little spendy for fairly sparse books. Are they worth what they cost, or can the info be better obtained elsewhere? What's appealing to me, is they maybe give terse directions for doing things properly, so I could use it as a 'quick start' guide, then maybe build on them with more in depth documentation later. I'm thinking of the pruning guide in particular. For the safety guide, is it 90% useless common sense with a little interesting stuff, or is it a useful book that can be repeatedly referred to?