Advantage of old style seatposts, you can use the hollow tube to run a loop of cable out of the top around the saddle rails
and back in again then fixing the other ends to a plug held in by using a longer seat tube mounted water bottle cage.

I recently got a Brompton Penta-clip. it is a premium saddle clip its micro adjustability removes the
notchyness of lesser saddle clips, and as its mostly aluminum, weight is reasonable ..