Thanks for the careful read of my wall of text
...You're right, a 1972 or 73 birthday doesn't mesh with him celebrating his 30th in 2005...d'oh! Time for another revision.
He was born in 1975.
His parents were still killed in 1983, making him 8 years-old instead of 10 or 11 as I previously suggested. (interestingly this is more in line with the comics version)
He drops out of Princeton in 1996 at age 21.
He returns to Gotham seven years later in 2003 at age 28.
He celebrates his 30th birthday in 2005. (You'll notice this revised timeline is still assuming BB takes place over a couple of years)
Rutger Hauer's mention that the Wayne's were killed 20 years ago still fits.