Fit gets really crucial as the mileage goes up. Things that you barely notice 10 miles in can be excruciating @ 50 miles... hand or foot numbness, butt or taint "issues", etc. But those are all ancillary to the real reason to get a fit that works: knees.
Just remember little changes go a long way... you mentioned an inch... that'd be a BIG change! Just go easy at first and listen to your precious knees.
I don't know a better friend to a middle-aged man than a good road bike. Well, maybe a still-horny wife.
Edit: I like to bring the tools necessary to make fit adjustments along on a long ride (when I'm messing with fit, I mean); you can really feel small changes once you've "acclimated" to a given fit for say 10 miles. I mean, raise or lower the seat by as little as 1/8" and it's like "whoa!".... I can feel the changes (and their effects) much better than if I'm just sitting on my bike out in my man cave "imagining".
