Eliminate 10m circle and allow players to jump or step putt if they first mark their lie back one meter. No runup allowed, just allow one step prior to the jump or step putt. No need to worry whether they released the disc precisely before they landed. The only stance violation would be when the group observed the player did not mark back a meter before executing a jump or step putt.
This proposed rule change eliminates: (a) the need for a timing call, (b) the player getting an advantage releasing the disc in front of their original lie, (c) a running long jump putt, (d) the time and expense for marking a 10m circle around each target, and (e) the current discrimination of the arbitrary 10m circle that prevents lower powered players and kids who need to jump closer than 10m to generate enough putting power, especially uphill, for accurate putting like the big boys.