It's almost been a month since I grafted the tomatoes, we've lost a few, but the survivors are doing well. If travel plans hadn't interrupted, I'd have grafted a week later, but for my first try, I'm impressed with the results.
Over the years I've learned that tomatoes are very hearty growers and they forgive a lot. I also know that if you plant a tomato in the ground up to "it's neck" Roots will form all along the stem for a better root system. Since this will still happen, these plants won't be buried as the upper grafted part would root, negating the grafting completely.
Here you can see all the new rootlets. I've never seen tomatoes do this, vigorous root-stock indeed!
The plants were in a healing chamber with no light and high humidity. I gradually reduced humidity and added lights. This batch was moved completely out of the healing chamber and under lights with a fan to help make their stems strong. I'll start hardening off later this week.
I'll have one ungrafted and one grafted tomato plant for each variety, sot the experiment will last all summer.