i tried grafting some heirloom tomatoes this past spring with very little success but did end up with 4 to plant. they are all doing well and producing tomatoes and are growing in hoophouses or high tunnels. the rootstock is estamino. since we plant tomatoes following tomatoes organically there is a good chance that soil born disease is present. the rootstock is very resistant to soil born disease, or so they say.
my grafting problem was due to improper timing of starting the rootstock seed and the scion seed. the rootstock should have been started a bit ahead of the scion.