Wasn't rocket salad honestly. The tent is flat underneath. Just a board. The c rails can go let to right or back to front. As it's not square, the rails need to be cut if you go one way or can be used full length if you go the other. Still with me? Well, I left them full length which meant that the tent would open sideways if I mounted the rails with the original brackets. This was very neat as the c rails dropped into the natural gaps along the roof rack. Seriously, there is no way you can still be following this.
This allowed the tent base to pretty much sit on the rack giving great support. BUT it was so low that getting to the zipper was a tw@t. All I did was lift the tent, leave the c rails in place and twizzle it 90 degrees. The c rails now sit across the rack not between the slats. This has raised it about an inch. Now, getting to the zipper is easy. All I needed to do was make some new 'keeper plates' which were wide enough to span the slats rather than the thinner rails. On the awning front, this SHOULD bolt onto the side of the rack. But, when it does, you cannot get to the zipper 9of the tent) again nor the holes to put the window supports in. Are you really still with me?
So I made some new keeper plates and dropped the awning onto the rack feet / legs. This means that there is plenty of clearance to get around the rain cover now. Honestly, not sure pics would help. Drawings might or coming round to my house maybe. It's not complicated really, just took some trial and error. I am happy that this really is the best. Will do some pic stuff when it's not night time.
I'd be saying WTF too if I were reading this.
Chris