Hope this is good spot to post as I think problem is more fglrx related but also software (mythtv) related.
I've got Cat 8.10 working OK (kernels 18.104.22.168 and 22.214.171.124) and there are lots of resolutions to choose from when right clicking on screen in X (kde). Currently running at 1400x1050 but had same problem at 1280 x 1024. When I start mythtvfrontend, the program changes the resolution and the mythtv text/screen is so large that I can only see part of it.
Same basic problem with Catalyst 8.9. Similar problem with 8.5 but not as bad.