DOUBLE WRAP THE FLIPLINE. For removals, I like to use a steel-core flipline. When the spar (not spur, which is another word for climber/spike/hook) is smaller diameter, especially if it has smooth bark and wet, like alder or maple here in the PNW, I will sometimes wrap it so that it does a 540*, instead of just a 180*, turn. This will cinch around the tree if you spur-out/ kick-out (your spurs slip out of the tree). Most always you will not need to double wrap, but it does give you lots more security and stability in certain situations.
SHARP SPURS Always keep your spurs PROPERLY sharpened. Dull spurs from walking around on the ground, are a hazard. Also, watch out for them barking-up, collecting bark between the spike and the stirrrup, which will prevent them from penetrating as deeply.
RUNNING BOWLINE AND GRIGRI AS BACK-UP TO THE FLIPLINE/ WORK POSITIONING LANYARD WPL FOR CHUNKING/ BLOCKING DOWN TRUNK WOOD I use a running bowline around the spar with a GriGri attached to my bridge or center D-ring. This GriGri is something that I already have, which costs around twice as much as a Beeline eye-and-eye friction hitch cord, but will not wear out, nor overheat and glaze. Most climbers use friction hitches, which I do as well, but a GriGri is something that I find useful for Single Rope Technique SRT and Doubled Rope Technique DdRT. It is easy to release under load, and easy to check to see that it has the rope oriented the proper direction (rope bag end/ tail of the rope/standing end goes with the hand icon stamped on the GriGri, and the working end which would go to the running bowline gets the climber icon).
This system always has a second attachment point for while you are running a saw (the running bowline is below the flipline).
If I am using a rigging rope to pull the spar over from the bottom, I will tie it with a running bowline around the spar about a foot or two below the top, with the knot on the opposite side of the falling lane/ direction, flip it over the top of the spar and lower off with the GriGri, on the falling lane side of the tree. When you pull it over, the knot will not be buried under the spar, and it will be able to be untied. VERY IMPORTANT, give yourself some space from the top when you set your running bowline, and cinch it tightly, and make sure the knot is TIED DRESSED and SET TDS. When you run it over the top of the spar, it will be pulled upward by your force downward on the other side.
You can also just accept that it will be buried if you choose to lower out on the falling lane side of the tree. THIS IS SRT, SO CERTAIN FRICTION HITCHES THAT ONLY WORK FOR DdRT, WILL NOT HOLD YOUR ENTIRE WEIGHT.
As the rigging line may have been damaged by logs falling on it, etc, always check it. I keep my flipline loose around the spar and walk my way down while lowering (not climbing down), sort of, in the event that there is unknown damage to rigging rope and a failure, I have a backup.
I don't worry much about lowering out on my climbline without the flipline, though I watch for puffs/ picks/ cuts in the climbline as I lower down.
RING-AND-RING FRICTION SAVER WITH PRUSSIK-AND-RING, FOR FLIPPING LOGS FROM THE TRUNK An alternative system is to use a ring-and-ring friction saver FS strap (not a cambium saver leather sleeve) with the prussik-and-ring that allows you to adjust the distance between the rings. I have the longest, maybe 72" strap with the prussik.
If you wrap the FS around the tree and adjust the prussik-and-ring such that the rings stay about 6" apart and use a DdRT, and have not left stubs from limbs, you can lower off of a limbless spar however far you want, to where you can SAFELY flip off logs. This is more advanced than chunking down with snap-cuts. A pull rope can help. BE SURE YOU CAN CUT YOUR FACE CUTS ACCURATELY ON THE GROUND BEFORE FLIPPING LOGS. YOU MAY WANT WEDGES OR A PULL ROPE ON THE TOP OF THE LOG. THEY MAY BOUNCE A LONG DISTANCE IF THEY DON'T LAND FLAT.
You can lower down, say 10', from the FS, put your weight on the spurs and flipline, double check that your snaps/ 'biners are secure, then put slack in your climbline and shake your FS down to you. Adjust that 20' of rope though your friction hitch/ GriGri, so you have a second tie-in, then cut your next log.
The DdRT with the FS, or the running bowline and GriGri, allows an immediate exit, single-handedly, in the event of an injury or hornets, etc. If you cut your arm/ let open, you will not be spiking down the tree very well, or very fast. You could bleed out before you can do anything to get to the ground. If a hidden hornets' nest is disturbed, you will be hard pressed to spike down safely while being assaulted by a hundred angry hornets. This single handed, pre-set emergency exit line is important, IMO.
A blood stopper kit could be a lifesaver as well. They're about $20 and can be carried on your harness. Hopefully, all it will ever do is sit there, nice and bright, with its First Aid Cross symbol on it, making you look like a prepared professional, never to be used.