The best t-pose is….. No you dont need to spread your arms into a tee pose. All you must do is allign the white dots and face forwards and press both grip buttons. If the tracking balls are too high you can adjust leg height in the driver4vr calibration and make sure you press enter to apply cm. This mostly happens on anime characters with poor bone structures for IK tracking.
Do you have any tracking issues make sure you watch my guide to setting up calibration Link (you will have to turn volume up to hear instructions.)
EDIT: It is also best to measure your real height in real life as it hugely effects body tracking. Setting your real height to your real height would give you best results.