The OP used frozen concentrate, and I used "Welch's 100% White Grape Peach Frozen Juice" concentrate and we both had great success.
I actually have a book on making wine called "101 Recipes for Making Wild Wines at Home: A Step-by-Step Guide to Using Herbs, Fruits, and Flowers" by John N Peragine Jr. and Lynn Keay that suggest making some simple batches of wine using Welch's grape juice to learn the basics steps before doing a "serious" wine. Personally I never tried it, but have to assume it must work since they recommend it.
I'd look for concentrates with the least additives, but concur that the preservatives used, if any are not a problem. I think I've only used Welch's, and Orchard Hills from what I recall, and both worked well.