Mark, Do you have a rigging eye (flemmish eye?) on the new tail? Stitching the messenger line alongside the 3/8 may be too fat. You can make a rigging eye by pulling the cover back on the bitter end, cutting the core back, then stretching the cover past the core, then fold it back to make an eye (stitch it). Tie the messenger to the eye. Or, I've also just wipped the ends and loosely siezed the two lies together in kind of a butt joint. good luck.
