I know how to taper a line (removing "case/cover" and burying it into the core). I believe this is what chris is explaining also. I hadn't thought of removing the core and leaving the cover- which is what you are explainging- usually because the core is the strength and low stretch part of the line and generally has less abrasion than the cover. As for weight.. not sure which would be heavier.
On the return line there is more than enough strength in the cover to do the job. The lines are way over sized so you can grab them easily not becuase they need strength. I have removed the jacket going to the head all the way to just before the cleat. Then I removed the core from behind the cleat to the last snuffer patch.
It has presented no issues as far as handling the line, There are no kinks going through blocks any more, and it does not burn the spin pulling through the hoop either. After a little over a year, I do not have any of the line burns on my spin I used to get. It is a little harder on the top halyard pulley block. I have not found 1 yet that lasts very long and with the tapered top, the thinner line they have to replaced fairly regularly.
Matt
