I'd love to come for a play and do some wide fields Paul! I'd also like to test our 70-200 f4L lens and even our 16-35 2.8L II lens (although I think the latter would be crap for astro).
Doug, the macro is the only non L lens we use, which is saying something. I have no experience with the other lenses you mention sorry.
Canon does however publish MTF graphs for all their lenses... if you look up these you should get an idea of the performance. Perhaps look up some L lenses so you can see what sort of graph you are aiming for.
Here is a link to the US canon site which has MTF graphs for their lenses:
http://www.usa.canon.com/consumer/co...5&modelid=7400
Enjoy!
Dave.