The diameter of the shade tube has a lot to do with the length of the shade.

The minimum diameter is of cource limited by battery diameter. The motors have different gear ratios and voltages.

The larger the shade "distance spanned "

the bigger the tube diameter "required to prevent tube deflection "

the more springs required to counter balance

the greater the number of batteries and

the higher the gear ratio on the motors.

There are complex calculations involved and the tolerances of individual components vary slightly, making it impossible to perfectly match two shades without some form of active feedback loop connecting them.

These are essentially blind shades.