I have found that, especially for someone who has not ever (or not recently) ridden on a road bike that the concept of "good fit" is a moving target. I think that your initial fit will be just that, and you will need to think in terms of changing the fit as you 1)get used to riding in a less upright position (that's a mental thing), 2)your muscles get stronger and 3)you get more flexible. For example, riding in an aerodynamic racing position would initially put 'way too much pressure on your hands, your lungs would feel compressed and your neck would get sore from holding your head up. There would be other aches and pains as well. I would recommend that you start with a relatively upright position and set your bike up so that riding on the hoods is reasonably comfortable. Pay attention to the comfort of your saddle, so you don't ride with a hunched back. What happens after that is a matter of getting used to the bike, riding more miles, getting stronger and more flexible. You will know when it is time to change your bike fit because you will find that you go faster when you tuck down further and it doesn't hurt when you do that. I love road bikes, always have. When I got back on my custom road bike after 12 years of not riding, I found it a little uncomfortable because I'd lost flexibility. After a couple of months, it was perfect again because I'd regained most of my flexibility and I'd gotten stronger overall.
I feel that you would benefit by going into the fitting process understanding that your initial fit may well be different from what you have in 6 months or a year from now. If the frame is sized properly, it will support all those variations in fit. You change stems, number of spacers, maybe even handlebars. Also, I can't emphasize enough, if your saddle is uncomfortable, it probably won't get less so as you ride more. I pig-headedly put on 1000 miles on a saddle that hurt every time I rode it in the hope that it would get more comfortable. I also didn't want to admit that I'd made a mistake. When I got a different saddle, it was just amazing. When my daughter got her road bike she tried valiantly to like the saddle that was on it but finally admitted defeat and tried others.
I hope this helps.
-soma5