preservation Vinegar blends

I played around with a few for years before settling on recipes for commercial purposes. They all have qualities that when used in combination with other ingredients can have great results. I'm a southerner and true to certain uses of vinegars. Particularly, I'm a big fan of paring tomatoes (high acidity) with vinegar as is common with many BBQ sauces. They all achieve a certain "pickling" effect if used in the right quantity and can impart a subtle flavor of difference in reaction to the other ingredients. Just gotta experiment and find out what suits your palate. White vinegar to me is akin to using white paint for a picture, a blank baseline. Other vinegars already have "color" added to begin with in this sense. Some things (or colors) mix better with those vinegars already having a "color" or unique "flavor." 
 
Not sure I've answered your question but would just say "experiment."

I don't mix vinegars. I look for the vinegar that has the flavor to work with the sauce I'm working on. That is how I have done things, but that does not mean that is the only way to do things.

Mixing vinegars is an interesting idea that can impact sauce flavors as much as mixing several peppers in a sauce.

Experiment and if you feel so inclined, please share how things are working out.
SL

Have not mixed vinegars yet, but may experiment this season.  I prefer to use apple cider vinegar in sauces, white vinegar for pickling, but a dash of balsamic in a sauce could be interesting.  Also rice vinegars used in the past for a quick marinade to cover some cooking. 

I do add white balsamic to others. It adds some sweetness when needed. Red wine vinegar is a neat option for ripe jalapeno sauce but i normally just use apple cider vinegar and lime juice. Hab, ghost and bonnets i like cane and/or rice vinegar. Baccatums i like rice vinegar also but a couple others are good too like white wine vinegar.
 
I dont use white vinegar for anything but cleaning.