I reckon with the lenght you have, Use a piece of cable try in it with the slots pointing side ways.
What is the length of the grate. It looks close to 600 long.
I see you have riveted the diverter on. Bloody good move mate.
You may have to add a support under it from top to bottom to stop it from bowing
or pulling out.
But, That is a bloody well done build mate.
Thanks for sharing.

What is the length of the grate. It looks close to 600 long.
I see you have riveted the diverter on. Bloody good move mate.
You may have to add a support under it from top to bottom to stop it from bowing
or pulling out.
But, That is a bloody well done build mate.
Thanks for sharing.