"I had better
 survival with the sugar blocks"

There is little besides the acetic acid and water in vinegar regardless of which vinegar you use.  The bees can use the small amounts of acetate as food.  After all, acetate is a common metabolite that living things routinely use for all sorts of biosynthesis.  Tartaric acid may not be nearly as easy for a bee to metabolize.  As you do not heat the sugar, vinegar mix I doubt if much, if any, HMF would be produced because I doubt if you even invert very much of the sugar.  After all, honey is more acidic than such a vinegar additive which will only knock the pH down to about 4.   HMF is not a problem in honey unless it is heated.

It would probably be safer to use a distilled vinegar as the distilled product does not contain the small amounts of undigestible cellulosic gums the bacteria in apple cider vinegar produce.  Bees do not need the fiber in their diet.

Dick

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