Some people (including myself) wear both the wedding and the signet family ring on the same hand (pinky and wedding band finger).
This style can be seen on Prince Michael of Kent and Nikita Mikhalkov (Russian movie director).
US guys sometimes wear both the signet and wedding rings on the same finger - wedding one.
In the UK one can find people wearing both a wedding and a signet ring on the pinky - like Prince Charles and Prince Edward.
Also, some people take both hands' wedding fingers up - one with a family ring, the other one with a wedding band.
But the thumb thing - that's a beach thing or wear big jeans and white keds )))

Andrey