Just another cheap way.

Tie one end to the port grommet(with a bowline, or cow hitch, or two half hitches),
take the loose end through the batten,
then loop the loose end, TWICE through the starboard grommet, then...

The TRICK is to create an OVER-RIDE with the SECOND loop,
(you may have to guide the line to create the over-ride as you pull it)
the over-ride if done properly will carry the load.

Then put the loose end in v-jam cap, OR just tie loose ends together.
I UNDO the over-ride, by pulling the loose end in the opposite direction
of the over-ride (opposite direction it went through the grommet).