Forrest, Do you have a Sherrill cataloge yet? If not, call them up and have one sent. They have great illustrations of different climbing techniques, as well as great prices and customer service.
You need to stay tied in at all times, so if you are spiking up a tree and come to a branch, tie in above the limb with a second rope, before undoing the lower lanyard. There is a picture in The Tree Climber's Companion(page 37). Some guys use a double ended lanyard, other use a splittail on their climbing line. There is a picture in The Tree Climber's Companion(page 53).
Climbing with spikes is only for removals. Those guys who spike up trees they are trimming, are unethical, because they are doing more damage than good. If the customer knew the facts, they would hire a skilled arborist, instead of a hack who has not taken the time to learn to climb by industry standards.
The fair lead doesn't have to be a pulley. A screw link that fits over the rope will work ok too.