Thinking...
 

Asking Samson is a good idea; they've been helpful to me in the past. My instinctive reaction to the idea of the splice was mistrust: I like everything to look tidy, and having a hundred-foot tail emerge from amongst the braid of a rope will not be very tidy or symmetrical. Then the thought of undoing and redoing splices doesn't appeal either.
Perhaps I will talk my client into using a different method. After all, there's more than one way to skin a cat....
Thanks all!
Ben

Why look for a splice in both ends?
A more flexible approach is to find a suitable object to hitch
the line to with a few turns and an Anchor bend noose.
--a 6-8" dia section of log? (The log would be then tied on each
end back to ...

And what to you do for an encore--i.e., to what is this monster rope to be attached,
and how?

There are some rules re making highlines that will need adjustment for use of
such INelastic material (as I think such rules usually apply to nylon low-elongation
ropes used in SAR; I've seen this caution voiced for use of Sterling's "HTP" all
polyester rope, e.g..

--dl*
====