I've just fitted a plastic c rail to the roof of mine and have a cheap "maypole" awning/sun canopy that looks very similar to the pic. As it's only going to be a fair weather awning I've tiger sealed and self tapped the plastic rail to the existing gutter strip. Saves me holing any metal work. I've adhered it to all but the last 6 inches or so at the end as the pop top flares out towards the back and don't want it fouling. It seems strong enough but will let you know when I try it out.
The canopy was about £75, one of these:
https://youtu.be/jPQJK89U8jo
The plastic rail here:
https://www.ukleisureparts.co.uk/shop/awning-rail-c-channel-black-plastic/
Total cost was only about £110. So fingers crossed 😅