I have a 35 classic and love it. However, I know a guy who purchased a new 29 Fountain with I think a 496 mag. For some reason they are running the 1.65 gear ratio in the 29's with a 32 pitch prop and it is just a total pig on fuel economy. He told me how much it cost him in gas to get from point A to point B and it was just as much as my boat with twin 500's
This guy actually drives an extra 45 minutes to put his boat in at a boat ramp that is closer to the hang-out spot because it costs him so much to drive there in his boat. If the 29 you are looking at has the 1.65 gears I'd really get an accurate estimate of it's fuel consumption before you buy it.
And if you are considering a new boat, my 2 cents of advice would be to not look for a new boat but rather buy a used but bigger 3 to 5 year old boat.