Acid content of wine vs. vinegar?
Verjus (the non-fermented juice of unripened grapes) is going to be more acidic than wine, but I have been unable to find a number/concentration.  Probably because a lot depends on the grapes at the time of harvest.  The acidity of various vinegars also ranges, so comparing verjus to vinegar would require much more specificity of the types of products you are intending to use.  So, if you are choosing between wine and verjus, go for the latter.