Thank you very much for showing this.You also can use this solution:
outbackphoto - News - Improved Shooting with Compact Cameras (e.g. Sony*RX100)
I have just got the Sigma viewfinder - the missing focus-point is not a problem for me, you can learn that,
.... but there is no dioptri, and that is a problem for me, even I do not wear glasses generel, only for reading, but I have dioptri in all my other cameras, and I can see now how important that is = I do not like to look at a blurred frame without dioptri, so I think I will return the Sigma-viewfinder og perhaps use your solution.