Given that most modern frames are akin to a " swedish chopper" when it comes to head angles, i wouldn't worry about it too much.
By the time you adjust the seat forward 2mm and tilted it down 1o, you still won't notice any real difference in your seating position as its mostly fixed point relative.
Novocaine is right, in theory its about a degree per 1" on the headtube, but most of the change will come from having different handing forks rather than the alternation of the geometry i would think.