For a roller set where the least amount of volume is desired, how should the rollers be placed?

When the goal is to achieve the least amount of volume in a roller set, the rollers should be placed completely off the base. This technique results in softer curls or waves and minimizes lift at the roots. When the rollers are positioned off the base, the hair is allowed to fall more naturally without significant root elevation. This is particularly useful when a subtle curl or wave is desired rather than a full-bodied or voluminous style.

In contrast, placing the rollers completely on the base tends to create maximum lift and volume at the roots, leading to a bouncier style. Half off base placements can produce moderate volume, while half on the base offers a compromise between volume and softness, but still creates more lift than fully off base. Therefore, for subtlety and reduced volume, completely off the base is indeed the appropriate method.