Guide lines
I WOULD HAVE TO SAY FIRST KNOW WHAT TASTE PROFILE YOU WANT TO ACHIEVE,FOR EXAMPLE,i WANT TO MAKE - AMARONE,i FIRST NEED TO KNOW FIRST HAND WHAT THE TASTE PROFILE OF THIS STYLE OF WINE IS,SO LETS START WITH ABV,ANY WERE FROM 14/16 % BY VOLUME,THEN i TAKE MY RAW PRODUCT AND SEE WERE MY SG IS TO START WITH THEN I KNOW WHAT i HAVE TO DO TO GET TO THE END RESULT,MOST OF WHAT WE DO IS SUBJECTIVE TO OTHERS OR OUR OWN INDIVIDUAL TASTE BUDS,SO THAT'S' WERE IT READY IS,i TRY TO KEEP WITH IN THE ORIGINALY PROFILE OF A STYLE OF WINE, JUST ENHANCE IT .
I know that oak can make the difference in the primary,always keep in mind that with the batches we pruduce,(small) in comparison to pros.when to add is just as inportant as what to add ,are choices ,have to be timely as well as correct and that comes with trial and error.
I don't as a rule believe in bench trials,maybe it's because I rather take a 6 gallon batch and break it in to 3 gallons batches and have something to work with(Sm.volume)I also believe in knowing what my wines taste profile should be,and the characteristics of it,as well as what is its blending partners are,or is it just a blender on its own.I'm not sure I answered your question but it's a great subject...............
all winemakers tweak at one point or another,that's what separates the every day(wines) from the good ones I believe...think outside the box,experiment ,have fun.