Re: Paging Mosca Pescador: Switch rod cleanup, this aisle
I never tried a furled leader on a Spey line, but I'd probably skip it. There might be too much hinge. Feel free to experiment.
I think that the Ballistic Spey line that you have is a Scandi integrated line. You are probably best off with a 10 foot polyleader plus a few feet of tippet.