[Ltib] Using Profiles and Preconfigs

[Mark]

Hello

I am looking at using profiles and preconfigs to control builds for different 
products on the same platform.

My understanding is that... 

...preconfigs are copies of specific defconfig files, i.e. they contain all of 
the 
system configuration including toolchain, kernel, user packages etc.

...profiles are just the user package configuration sections from defconfig 
files 
between the 'Package list' and the 'Target System Configuration' entries.

My questions are as follows:

1) Are my assumptions above correct?

2) Do the profiles override the equivalent settings in a preconfig file? i.e. 
if 
a package is selected by the preconfig and de-selected by the profile, which 
takes precedence?

3) Is there any way to create a profile other than just 'carving out' the 
appropriate package section from a complete defconfig file?

Thanks

Mark