Road trailer - stone guards

Hi All

I am looking for some help altering my road trailer.

I have a relatively small, light trailer that works well for the very small journeys I do. I have replaced the deck with a longer piece that now goes to the front of my trailer. Now I want to install some stone guards so I don't have to put on a hull cover for long journeys.

I'm thinking that I should bolt on some more plywood from the front all the way back to the wheels. My issue is that the trailer is ever so slightly narrower and hence the plywood cannot go straight up from the road trailer or it will hit the hull, it will need to be angled outwards slightly. I don't think I should sit the boat further back as for now the dolly wheels touch the road wheel arch giving it a nice lock.

Would my best bet be to use angled metal brackets (>90 degrees) that bolt into the deck and then onto the ply? Any other ideas? I was thinking even a canvas around a frame would provide the protection without impacting windage?
Next step would then be a second level so I can help friends get to local racing.

The red flag has been invaluable - prior to having it I was rear-ended two times whilst standing still at the traffic lights. Both times people were stopped but looking down at their phones and slowly edged forward into it, I assume because it was down low and they were not paying attention.