Find Overburn Capacity
Found a good guide on figuring out the overburn capacity of a CDR (in Nero/Nero Express).
http://club.cdfreaks.com/showthread/t-59188.html
The gist, is that there's an overburn burn test in the "Nero CD Speed" utility that is installed w/Nero.
Error Codes
Logical Unit Sense Key, ASC and ASCQ Assignments - Sonic RecordNow will display these on errors.
http://www.isobuster.com/help/error_codes_/_sense_codes