that I should have a support across the middle of the car when the hood isn't up
I introduced a useful little tweak to my arrangement last year. I bought a few metres of 4mm shock cord from a camping/outdoor shop (Actually it was the hiking section of the Green Welly in Tyndrum).
Tie a couple of loops in it, then hook it over the centre windscreen wiper mount, over the windscreen and back the rear of the car where it loops over the spare wheel T bar. No need for a high tension, it's enough to stop rain turning the cockpit area of the cover into a bucket.
