I'm too am interested in know how much work would there be to use metal cover to replace plastic. I assume none, but need photos and proof of it done.
As for weld on hooks - I added 2 bolts on on each ends and found that when lifting heavy things from one hook just makes tractor unstable. I always try to use a strap or chains so it would be better balanced. If you use one hook- its best to have it centered just behind the lip.