Picture posting is enabled for all :)
All this talk of clips has made me feel obliged to offer an alternative. I have used a plastic straw. Somewhere on youtube there was somebody using plastic tubing to connect the two plants and hold them in position. It was in my price range so seemed the best option. I cut the potato stalk diagonally and then slipped over a short piece of plastic straw, and finally pushed in the tomato stalk with matching cut into the other end of the straw. It holds it nicely and seems to work ok. I did a couple more last week when the weather turned cooler. I have decided to not let the tomato root independently, keeping the graft above ground. It just seems to me that the potato part becomes nonessential if the tomato sends out its own roots. Could that effect the potato yield? We will see. My first plants should be going in the ground this next week. They will be in the greenhouse border though. I suspect we may have another blight year.