Attach a handrail,
Going to convert a trellis into a railing, will use a 45x70 as a handrail and want to hide the mounting between the handrail and trellis slats, which are made of untreated wood and will remain unpainted.
And you want tips on methods?
Wood dowel and glue at the ends of the slats and into the underside of the rail.
Make sure to be precise when marking and drilling the holes so it turns out straight and nice.