thumb allignment

I know tai chi instructor (Marjan Dogsa) who emphasizes such allignment, and not so the others.
Kumar uses such allignemt, but did not speak of it for the record.
HT usually emphasizes other allignments.

Schema is drawn a la Kumar central channel way.
Dillema is: do finger open from palm point or wrist joint (and palm point being tertiary).
http://www.geocities.com/djernej/pictures/locked_thumb.jpg