Will you have a car?
I've copied and pasted a response I gave on a similar topic. Perhaps you can contact some these wineries and ask your questions.
Here is a copy of some notes from an Austrian friend regarding wineries:
WEINGUT KNOLL----in Unterloiben, famous wines and an excellent Restaurant "Loibnerhof"
DOMÄNE WACHAU----Dürnstein: the only cooperative in the valley. Great selection of good wines.
WEINGUT SCHMIDL----just 200 meters down the road--Organic wines-good.
FX PICHLER----Dürnsein: the star of winemakers. Very modern and sterile-but good wines, pricey though.
next village is WEISSENKIRCHEN:
lots of great HEURIGEN there.
WEINGUT PRAGER: Famous Winery, great wines.
Next village Joching:
WEINGUT JOSEF JAMEK--the godfather of winemaking in the valley- good wines and good restaurant
WEINGUT HOLZAPFEL----courtyard with the Restaurant on a sunny day fantastic.
Next village Wösendorf:
RUDI PICHLER---a new star, very nice wines, expensive.
Next village Spitz:
WEINGUT HIRTZBERGER: the new Number One of winemakers.
WEINGUT LAGLER: Nice wines, great views, nice hotel.
These are just a few of the best from more than 500 wineries in the valley, but there is a winery on every corner.