Simple DIY Looks ok . Beats that ugly plastic rail.
Yes the kits are expensive . There is not really one size fits all . Passing rings ? ( Baaff Minnie the minx )
Made my own Standard plumbing supplies About £40.
Go plumbing shops ( B&Q etc) : 2 x 2m lengths silver coated 15mm copper pipe: Bend it to whatever curve you need ( simple spring pipe bender) Make centre and end point wooden supports to window wall
Fix standard plastic 15mm pipe supports to each support ( 3 in a row) Push in the two (bent) pipes to supports and pin secure with small screw.
Now the trick Only 3 or 4 passing rings . ( from standard rings)
You will need two intermediate supports . You only need them close to the centre fixing ( where the two rods meet) About 400mm either side. Just a simple thin ledge to go under the rail. Not attached.
I made my own 6 passing rings ( 3 either side) Cut out a section of standard cheap plastic curtain rings. to make the C shape. Only a few. Works just fine as its only over that last leading edge of the curtains as they draw
For a heavy weight full drop curtain do same but sub 22mm pipe
Can post some photos if anyone interested and thats allowed.
At last : Have new sewing machine on to finish making the curtains LOL ( another story .. could not beat J Lewis ready made and modify to width for full pleat )
ciao Ms Otis