When I use the SC on a tie out, I tie a stopper knot in either end of the SC and then clove hitch it into the line near the fixed eye of the main line.
With the thera band, I tie 2 knots in the main line 12" apart. 1 of those knots as right at the end of the bury for the fixed eye on the main line. 5" of thera band equals 4" of usable tube for tension. Then zip tie the thera band to the outside end of either knot.