cruisin on the highway?

We were debating if there would be any gain (more specifically in MPG) by adjusting the spark time for cruisin on the interstate. We're about to leave for a road trip to northern Georgia. So 8 hours of highway driving... we'll say 70-80 mph for the majority of the trip.
Would advancing it help any? What would the risk level be?
all of this assuming we are very light on the throttle getting on and off the interstate when we stop for gas

Just lookin for everyone's 2 cents...

 

The minimal gain isn't worth it... What do you get mpg right now?

 

i don't know... haven't had a working cluster for a minute so i don't have a good number as far as mpg goes...
you can advance the timing quite a bit at idle and little throttle but then get all kinds of valve chatter when you get on the throttle at that way advanced setting. Well, taking that tid bit, when you are on the interstate, just cruisin, you aren't under a heavier load as say accelerating, so you can be real light on the throttle. The thought was that you could set the timing really advanced, and make a little more power, resulting in a little less throttle, meaning better mpg to maintain the same speeds.
We were more or less talking in more of a theoretical sense.
I'm sure in a practical sense, the gain wouldn't be worth the hassle...