It doesn't really matter, one trunk or two, right or left. All that really matters is pruning properly and spreading the leaves out to intercept as much light as possible. I like your T trellis idea. What I'd do differently is have a third wire down the center. I'd put both canes on that wire one running each direction or both running each way. It's alright to have two canes on one wire. Then the outside wires would be to support the new canes growing out each way. This helps some to avoid wind damage to new shoots. But your plan is just as good.

Bart, the primary difference in the grapes you mention is your wine grapes are pure vinafera and the table grapes are hybrid vinafera/american. There is some difference in table vs wine but the vinafera/hybrid difference is bigger. Most hybrid grapes are much more resistant to diseases but it does vary from variety to variety. I am a primarily organic grower and I found vinafera a huge pain which took up way too much of my time so I pulled out my wine grapes this spring. I now have primarily hybrids and just a couple vinafera table grapes. Usually by now I have had to do 4-5 sprays but this year I have done only one and the grapes still look fine (even the couple vinafera look fine - their neighbors are all un-diseased and that must help). So, a rough guide is half or fewer sprays are needed; save your tank leftovers for them. As far as pruning goes I used the same for all types but I am not in to all of the subtle stuff of grape pruning. Some table varieties are considered better pruned to canes and other pruned to spurs, but I always used spur pruning for all my grapes. Scott

I too agree that most vinifera taste good, and even some of the hybrids, such as Foch, which is also my favorite wine grape for food. Franktank, in WI you have to use hybrids, no vinifera. Even last year, terrible summer and all, Frontenac made it to full ripening. I think the hybrids are interesting grapes, with more fruit than vinifera, but more difficult to make into nice wine. As a matter of fact for wine I prefer Frontenac, but only if mixed with some CA grapes for tannins. But the hybrids will generally shine in blends, which is what I do. Scott, if you get organized, a really nice bottle of homemade wine can be had for less than $3. My blends are typically 60% MI -40% CA. CA may be $1/lb for the grapes, and MI, $60/lb (at least locally). So the wine for one 720 ml bottle comes to about $2.30 a bottle. You have to buy from someone who will destem them for you, so you take home just the juice. You have to have friends who will do it with you. Alone, it is a drag. You have to keep track of your bottles so you can reuse them over and over. I use 22 oz. beer bottles with beer caps, which I got from the refund bins. And you have to find a press at a garage sale for $10, though I have seen a number on craigslist for $100 or so. Plus spent grapes make great compost, the one I usually give to the tomatoes. The easiest way to make good wine is to ignore the cultivar and go for the ripest, highest Brix grapes. In the old days, when California Grape in Detroit had the crates outside, it was easy enough: you'd just buy the grapes with the most flies and wasps on. With ripe grapes, it is easy to make good wine, far easier than to make good beer.

Don't know about Fredonia but Frontenac can make a very nice red wine. It tends to be a bit high in acid so you may need to blend in some years but here in the Hudson Valley it's pretty vigorous and easy to work with.