I'm looking at replacing an existing fence on a concrete retaining wall with a horizontal slat fence using flanged aluminium posts and Merbau slats. Any suggestions and/or advice would be appreciated.

The basic design would be something like in the photo but I don't plan on using any type of prefabricated fence panels or associated hardware.
A complicating factor is the proposed fence line includes a couple of obtuse angles.
I was thinking of using either timber batons or lengths of aluminium angle screwed to the posts. The slats would then be screwed/nailed to the timber or aluminium angle.
For the angles, depending on the choice of timber or aluminium, I could either rip the timber batons at an angle or else have the aluminium bent to the required angle.