highfly:
GS is irrelevant when considering your requirements.. surely
Ground speed is what determines climb gradient; i.e. "This departure requires a climb gradient of 425 feet per mile. Those miles are ground miles, not air miles.
IE.. for a given TAS you will get a given value of Lift assuming all other factors remain constant. ( Your V speeds are surely not derived from GS)
V speeds are performance values, which are expressed as indicated airspeed, not true airspeed and not ground speed.