After testing Phyxx Keyer in Motion 5, Motion's own keyer, old Primatte and old Keylight in Shake; as expected, up to date Keylight in FCP7 keyed the best.
So just like Eco, the workflow will be:
Edit green screen footage in FCP7;
Use Keylight in FCP7 to key footage;
Use basic garbage mattes in FCP7;
Export each scene with embedded alpha channel using Animation or ProRes444 codec with colours set to millions+;
Import FCP7 exported files into Shake and composite background, light wrap, colour correct etc;
Export from Shake back into FCP7
What is going to interesting in Shake is how I can use the FCP7 exports alpha channel and add in more travelling mattes for things like the clip board and other hold out mattes. I assume I can multilayer the alpha channels and then use the output from that multilayer as the final matte on the original green screen clip? One to play about with and test I suppose.
Of course I could buy the new Keylight for Shake and have no problems/workarounds for hold out mattes but that is £450+vat .... may be one day!
The test key I did was of me standing around and after some tweaking Keylight did the job with the aid of a simple garbage matte. I used an old screen grab of the hanger interior and it looked pretty good, really brings the background to life.
Just need to find the time to get cracking on it all !!