Tach for an R3T

Okay guys, I've posted about this before buy now I want to try and get some firm answers.

I want a tach for my R3T. I want to hear from Captains who have successfully mounted a tach on their R3T. I'd like the following info:

Type of tach;

Step by step instructions and

Photos.

Can anyone help? Has anyone actually done this?

Thanks.