My club, the tow pilot inspect the rope and both links at the beginning of the day. The ground crew puts the rope away, another chance for inspection.
We use 3Ply Twisted Polypropylene , 7/16 " is the main rope 200ft, 5/16 weak link on the tow pilot end, 1/4" weak link on the glider end.
This works for all gliders except the Janus C which specifies in the POH a heavier weak link, it gets the 5/16" on both ends.

5/16" is to strong for the SGS 1-26, 1/4" works for the 1-26, Grob 103, 2-33 and most single seat glass with no water.

The main rope has an eye splice on each end. The weak links have eye splices with the tost or schweizer ring in the eye, a plastic tube over the 1/4" protects the ring from chaffing on the rope. Eye splices to swap the weak links are easy for the appropriate ring. Students can eye splice weak links before solo.

The ground crew presents the weak to the glider pilot before hook up. As slack goes out the glider pilot and ground crew watch for knots.
We will shorten the rope as needed for wear, down to about 150ft minimum. Normally by the time the rope is that short it is worn out from dragging, whipping and UV.
BillT