How about my inquiry Pete,
What about Nut flavors & Cream flavors (two different categories)? Which would you add to flavors in those two categories - vinegar or lemon?
That's what makes DIY so fun!
It is YOUR choice what to add to your juices.
This is how I might approach this question:
What would the mix taste like if I did start to taste the acid I have chosen to use?
Nuts plus vinegar = May not be too bad
Nuts plus lemon = Probably not too good
Cream plus vinegar = Probably not too good
Cream plus lemon = May not be too bad (Lemon Meringue Pie?)
Then I would flip a coin, heads its vinegar, tails its lemon juice!
After that I would decide to use malic acid because it is flavorless and just tastes sour!
I agonize over this issue all the time Mick, join the crowd!
As an aside...
Nuts and Cream are usually used as accent flavors and typically don't stand by themselves, but then again that is IMHO. And YMMV.
Good luck and let me know what YOU decide!
Pete