I just cleaned out my greenhouse this week and I picked almost a bushel of mostly green tomatoes. So, I looked for green tomato recipes in the internet and ran across a "Green Tomato Salsa" one. It was excellent I ended up making 33 pints this week. So I don't know why you can't substitute green toms for red ones, but I would use fresh peaches if I was doing the recipe. They may not have the right consistency after being canned twice. (maybe like syrup)
Here is a great green tomato salsa recipe and I am sure you could adapt it to use the peaches in it, too.
http://www.food.com/recipe/green-un-...canning-393491
I changed it a little bit. I put no onions in, my husband can't eat them, no oregano, I don't like it, no pepper, no cayenne pepper, and a little more sugar (just enough to take the sour out of it) nor did I follow the quantites to the "T"..I winged it with the ingredients I had or was too cheap to buy all of, like the red bell peppers. Here, they are $1.50 a piece right now.
Then I canned it in my pressure canner at 5lbs. pressure for 10 minutes.