Acidity in Welch's Wine

I know that most people use two cans per gallon, rather than reconstituting the juice according to the directions, in making wine from Welch's frozen concentrate. They do this because Concord grapes are too acidic, or so I thought. Jack Keller's recipe calls for

2 tsp of acid blend, though, and that makes me wonder if reconstituted juice, sugar to 12% PA, and no acid would make a better wine. This is what I have in mind ...

Ingredients:

4 cans Welch's (or other 100% concord) frozen concentrate water to reconstitute (12 11.5 oz cans would be 1 gallon plus 10 oz) sugar to 12% PA (a pound?) sulphite (1 campden tablet or equivalent) 1 tsp peptic enzyme

Procedure:

bring water to a boil, then remove from heat dissolve sugar and cool (I usually immerse the pot in cold water) stir in concentrate and pour into fermenter add sulphite and enzyme, then pitch yeast

Notes:

This works out to more than a gallon, but I think that's a plus in that there's less topping up. In fact I often make "1-gallon" batches with

1.5 gallons of must (a "vintner's gallon?") to avoid topping up with a different wine. Nutrient might be helpful, but I think it's unnecessary in grape juice. Until I heard that people were adding acid to the 2-can recipe, I would have made the above recipe with 2 cans.

I'm planning on making a wine from frozen concentrate, maybe one batch with 4 cans and another with 2 cans. I know some people are making these kinds of wines; what is your experience? Does 2 cans plus acid result in a balanced wine? Ever try it without additional acid? How about 4 cans? Crushed and pressed Concord grapes?

Erroll