Also, lets say you're doing a distance race and basically on one tack/jibe for many hours and you wanted to run the sheet from the clew, theu a block on the clew and have the end attached to the shroud (cleat, ball and loop, etc.) to make it much easier to work the sheet:

In the case of the spin sheet being run with:
A pagtail burried in the middle of the line tied to the spin clew and the ends tied off or tied together at the back:

That method kinda make it impossible to so that.

Any other options? I may go with a block on the clew on the port sheet side/so when sheeting on a starboard my crew has a 2:1 on the spin sheet.