I have made some mistakes with buying plywood from big box lumber stores myself. My TV stand that I will post in my build thread in the future was a disappointment to me. The veneer was rotary cut (made like a pencil sharpener), so I ended up with a plywood veneer that soaked up way too much stain and the grain pattern was a blotchy mess. For my last project, I opted to pay 3 times as much for cabinet grade lumber. I haven't seen anything that comes close to baltic birch in terms of structural quality.
Maybe I will get to hear your system a few years down the road. My nephew is starting college in Ames this fall, so it may be a side trip. I don't know much about wine, but I am an all grain beer brewer. The thought of working in a winery sounds nice. There is always the voice in my head telling me to start a brewery, but it would probably be tough.