*Quote - ... But the default ground plane mat is very horrendous! So I really wish they would in the next edition of Bryce change the mat to one that loads real fast like the basic gray. *

Here is what I do:  change the default ground plane to basic grey.  Set 'Document Setup' to your usually preferred size (if it is different from the default).  You can at this point change anything else you want, such a new sky - but I don't bother.  Finally, 'SAVE AS'.. this scene into the same location as the Bryce application file, naming it 'default'.   This is now your new default startup scene, complete with basic grey ground plane.

I used to do this in Windows, but now I'm on Mac and it works there too.  So far Bryce 6.3 seems to be working well with my iMac and MacOS 10.6.2.