not asking for the calibration is caused by this entry being absent in the initflashfiles.dat which was moved by me to the zzz_My_Start_Menu_OEM:
Directory("\Windows\StartUp"):-File("Welcome.lnk","\Windows\welcome.lnk")
And here is the regkey that tells it what to run:
;Skip welcome except calibrate and timezone
[HKEY_LOCAL_MACHINE\Software\Microsoft\Welcome]
"Disable"=dword:FFFFFFED
But, yeah, there is some stuff that you must leave in....