Here are mine in a greenhouse one year after planting in 10 gal pots. The two wire trellis is already full. Right now there are 11 pots on 32 linear ft of trellis but that will be reduced to 4-8 after I see how vigorous they are and which varieties I like best. The plants grew at least 20ft the first year. Haven't decided yet if the foliage will stay on top of the wires or hang down each side. In the past two in-ground vines were on this trellis. They hung down each side but were overly vigorous hence the pots to give me better control of water and vigor. I'll get sweeter and more flavorful fruit by shorting water some.

I have a few thoughts... I've tried cane pruning on a couple vines, and I couldn't tell any difference in the fruit quality or the yield so I abandoned the idea. I find spur pruning to be quicker and a lot simpler. In my opinion, either method is fine unless you are dealing with one of those few varieties that do no produce fruit on the first few buds. Dis-regarding those varieties, just go with what you know and what works for you. The only other reason I can see that cane pruning would be better is that buds with high light exposure usually produce more fruit. With cane pruning you can choose the canes that got the most light whereas with spur pruning your choices are very limited. We have plenty of sunshine here, so I don't see it as an issue, but in Oregon (not as much sunshine) it may be more important. I'm guessing the distinction between table and wine grapes is because, with wine grapes, you don't want high yield (many clusters are often dropped at veraison) so being a little less fruitful is no problem. I've visited several commercial vineyards here in Idaho. We have both table and wine grape vineyards in the area, and all that I have visited are spur pruning and producing very high quality fruit. I know that what is best for commercial growers is not always what is best for "backyard" growers, but in this case, it does show that spur pruning is commercially viable (at least in the Snake River Valley). Fruitnut, I think it was you who, a couple of years ago, advised me to visit the U of I research facility. I'm really glad you did, I got some vines (cuttings) from them and learned a lot about viticulture and fruit growing in general. Thanks for the suggestion.

There are many different ways to train grape vines, usually a grower will determine the best method based on variety and climactic conditions. I'm not familiar with Kay Gray and I am not sure where you are from, so it is hard to give advice. I'm guessing you are in zone 5 (would help to know where) and Kay Gray is a cold hardy variety? I prefer to grow the cordons low (like your pictures) and allow the canes to grow up to the top wire (VSP method). I grow mostly vinifera grapes, so they are more suited to that method. Usually labrusca (American) grapes have trunks up to the top wire and the canes hang down. Sometimes one trunk is used, sometimes two. Looks like I am not really answering any of your questions - the accurate answer is "it depends". One thing I notice in your photos is that the trunk is not straight (has a severe bend). That is usually not desirable because straight trunks help support some of the weight of the vines. It may work ok for you, but make sure it is securely attached to the trellis and that the trellis is very sturdy. Mature vines with a full fruit load can be very heavy. Finally, here is an article on grape growing that may answer some of your questions and it has some useful pictures: Here is a link that might be useful: Grape Growing

You might be over fertilizing it... grape vines like it on the lean side, in order to put more energy into fruit production instead of growth. I'd wait till the regular pruning time... and not fertilize any more. I have heavy clay so when I planted my grapes, I heavily composted them... and am paying for it in huge growth... but I am hoping it lasts for awhile, in the end, better soil.