Hi Jerry & Co
Here's what I ended up with:
I couldn't make the tent as large as I would like as I made it out of offcuts. Therefore I can't use it with a central pole as I have to sleep diagonally. That said, I'm pleased with its performance so am going to make do with it for now, and since I know it holds up, I'm going to add some more details, like a few elastic cords to help with the tension, and some toggles to pin back the entrance.