I have used Tinkercad
The autor (https://www.thingiverse.com/Jubaleth/about) claims that he has no time for modify the desing and make it compatible with an another sensor support so I've dedcide to help him because his desing it's really really really good.
The original desing https://www.thingiverse.com/thing:2002778 works with 18mm proximity sensor, but I need it for my 12mm sensor so, I download the original stl file and imported on Tinkercad and then I try to modify the sensor support using the basic tools (i`m not a designer) after a few attempts I came with this, that is acctually came pretty good and works perctly with my 12mm sensor.
I hope you like it and can use it.
Thanks to Jubaleth