The various forms and colors are of minor importance.
Except when the minor siddhi's manifest. Then the color and form is very important although the range of minor siddhi's overlaps. But actually this question applies to sublime realizations as well short of the major siddhi of enlightenment.
Yes, it's this question. With a twist.
Does progress with one Tara carry over to others?
For example: if someone does a three year retreat on Green Tara and completes approach, then begins a three year retreat on Red Tara, will progress come faster and easier the second time due to the Green Tara practice?
You will need to ask an intense Tara practitioner. Perhaps someone has addressed this in a namthar or perhaps Jamgon Kongtrul addressed it?
_________________Kirt's Tibetan Translation Notes
"Only you can make your mind beautiful."
HH Chetsang Rinpoche