For some ideas how to build your new wineador see my build thead ... it has helped many BOTL and in my opinion the most effective route in building a cigar wine cooler . http://www.cigarasylum.com/vb/showthread.php?t=50189
I can hold around 400-450 in my "28" bottle NewAir ... so an 18 bottle will be far less ... if I had to guess all depending on how they are stored I would say more around 300 or so give or take.
If I can help out in anyway with your build once it arrives let me know brother!