Twisting
Two turns per revolution is the whole machine. Raise twist and delivery falls in exact proportion — the energy per kilogram is what actually changes.
— kg/shift
All spindles at the stated twist and efficiency
Connected spindle power is not constant across the doff: balloon tension rises as the package builds, so treat the specific energy as a shift average.
Two-for-One Twister Production & Power Calculator — free, with the formula and a worked example, at Textile School.