I came across an interesting decal on the inside of a CSS-8-64, giving the stocking percentages based on demographic.  I haven't seen one before, its pretty beat up, but you can read all of it.  Here's what it says:
STOCKING GUIDE 
FOR 
VENDING MACHINES
| IF THE CUSTOMERS OF YOUR
 MACHINE ARE:
 | TRY STOCKING IT THIS WAY TO
 INCREASE SALES:
 | 
|  | 
| A - MALE | Coca-Cola....................66% Sprite..........................14%
 TAB..............................4%
 Fresca..........................3%
 Fanta Flavors & Mr. Pibb 13%
 | 
| B - FEMALE | Coca-Cola....................60% Sprite..........................16%
 TAB.............................11%
 Fresca..........................3%
 Fanta Flavors & Mr. Pibb 10%
 | 
| C - YOUTH | Coca-Cola....................62% Sprite..........................16%
 TAB..............................2%
 Fresca..........................3%
 Fanta Flavors & Mr. Pibb 17%
 | 
| D - BLUE COLLAR | Coca-Cola....................64% Sprite..........................16%
 TAB..............................6%
 Fresca..........................3%
 Fanta Flavors & Mr. Pibb 11%
 | 
MORE SALES MEANS MORE DOLLARS