I do likewise but we are sometimes required to ground taxy for prolonged periods, especially if low-viz procedures are in force. I do that at 100%.
I too select 100% before going from "Idle" to "Flight" mode; otherwise the Nr overswings briefly to 104%, which I don't like to see. As the Nr peaks, then cuts back after the second engine catches up, if on a helipad or in a field, I then immediately select 102% for lift off.