Originally Posted by davidpm
The next item is the actual line. I'm planning on getting 350' of line. 50 lbs.
There are several types of climbing ropes, static and dynamic, wet and dry. Dynamic stretches to absorb energy in a fall and wet is treated for protection from the weather.
If you go with the harness and ascender plan, you will only need a length equal to twice the height of your mast, because you will haul the midpoint of the rope to the top of the mast with two halyards and attach each ascender to a different half of the climbing rope for safety. Static dry rope would be fine. Of course, you will attach the halyards to the climbing rope with bowline knots and not shackles. Attach yourself to the mast with an ordinary safety harness and rope wrapped around the mast several time so if all else fails, you will slide down the mast slowly instead of falling to the deck.
Consequently you will have redundant systems and a backup.