I likewise prefer descending in the drops. There is definitely better leverage on your brakes aswell.

One thing I may suggest is when you get your bike see if you can get some truly top of the line brakes for it even if you need to pay extra. On my own road bike (got it used) I have Dura Ace brakes and then I got on my cousin's Trek 2.1 which is still a great bike but it has Tiagara brakes. And while those brakes will certainly stop me if I need to, the Dura Ace brakes can lock my wheel with practically half the force of the Tiagara brakes. Now that could be due to Brake pads aswell (I dont know what pads are on both bikes honestly) but I really never want to skimp on good brakes. Best part is they are some of the cheaper parts of the bike aswell.

I have to say I applaud you for noticing the form of the riders in the TdF and how they "relax" on the hoods you are far more perceptive them me is all I can say.

One thing I just thought I might warn you about are that atleast on my cousins trek the drop bars are both shallow and have a very sharp bend between the tops and the hoods which makes me smash my forearms into the tops when sprinting from the bottom of the drops. Might not be a problem for everyone but you may want to check it out before you buy the bike. THere is a chance you may be able to get the shop to change a few things for just a few dollars more and that may make you happy in the long run.

In any case: Welcome to the Funny Farm that we call a sport/hobby (Road biking that is).