Lubrication. I added one pound of uns margarine to 20 lb batch of dough.
10 lbs bread flour and 3 lbs cake flour.
I suppose you could use all purpose.
Never added any acids like vinegar etc.
The laminating develops the gluten, too much makes a tough brittle dough that doesn't eat well.
I find the cake flour softens the finished dough a bit.
I tried with straight bread flour and palmiers came out like hard shingles, so ....