rope lanyard can be cut with a pocket knife, much less than a handsaw under the right conditions. steel for me. just yesterday i knicked my flip-line with the 200, hardly enough to fray the cover but had that been rope it may have sucked it in and severed it. of course i was in a climbing line as well. i've heard accounts of steel-core lanyards being severed with a hard direct hit on a tensioned lanyard. i've also heard accounts of people who experimented on the ground by trying and trying to cut through one and couldn't. i don't know, if anyone has experience with this please give us your input.
046 is right on. internet as your only source of info is a bad thing with any research, but especially research like TREE CLIMBING. Take an intro to arboriculture class maybe, you will learn alot about tree biology, disease, pruning, all things which can make even a recreational climb safer. Read books and weather you want to join ISA or not, i've found their publications up to date and unwavering as to how to climb and rig safely. Take from the pros in this forum who are physically in the tree, every day. You'll be alright.
i was just gonna say about your split tails, if you just buy 5' pieces of climbing line (for a few bucks a piece) right from your arborist supply you can get them in opposing colors to your climbing line which can cut down on confustion when working your system. i find the blue against the yellow a dead give-away as to where the tail is and how my hitch is working.