If tension is controlled by adjusting the speed based on a load cell or dancer, the tension regulator gain may need to be changed or adapted as the roll diameter changes. A small RPM change will have more effect with a large roll than a small one, so gain should be inverse to diameter. This was shown to work well on a recent project (sample of one).
Tension is established by a percentage difference (ratio or draw) between driven points. At higher speed the tension regulator should have more authority to change speed to maintain tension. This was recently shown to work well with a pull roller (another sample of one). The spindles worked better without this adaptive control.