Easy!
Load up Bryce.
Change your cloud/sun/sky to what you want.
Check your render settings to what you want.
Change your camara view etc
Lose the default ground plane setting to something like Bryce default grey...(This will save render time)
go to  FILE, SAVE AS,
call it   DEFAULT.BR6 or BR5. 
But make sure this file is in your root Bryce folder!!!!!!!!!!!!!!!!!
Close Bryce.
Load Bryce and you new default setting should be ready for you.

I'm not sure but there might already be a file called DEFAULT.BR?. If so, just overwrite it.

Available on Amazon for the Kindle E-Reader

All the Woes of a World by Jonathan Icknield aka The Bryster

And in my final hours - I would cling rather to the tattooed hand of kindness - than the unblemished hand of hate...