so you started with 10', so now your max length is 8-9' or so and you're min is 5'? (maybe i'm seeing it wrong though) what's the min distance the hammock whipping can be from the end of the tree strap? seems like this might force you to have to hang from a larger span?
Minimum can be around a foot if you bring the end out closer to the hammock. This system does require a lot more cord to get the full range but is still simpler and lighter without the hardware. I suggest the 7/64 because you are doubled up on the cord on an average hang. On a close hang you do have a lot of extra cord.

Max length is about 1/2 length of line used if buried part is close to hammock

so the taper is just to get it through the eye of the needle or does it have another purpose?
helps get it thru the eye but more important keeps from having an abrupt transition inside the braid that could be a weak point similar to a bad knot