Installing oil pressure gauge

[Arthur Marks]

Hi, I want to install an oil pressure gauge to monitor my sludge problem in my B6 A4 1.8T Q. 

Primarily I would like to know where to install on the engine side. Do I need a T-fitting to go where the current oil light sender is located or is there a free hole with a plug I can remove? Bentley CD shows a plug inline with and opposite from the oil filter, and there is another plug on the oil filter holder for pressure relief.

Also, oppinions welcome on choice of electric or mech. I've heard mechanical are generally more accurate, but there's always the chance of breakage resulting in an oil leak inside the car. Is copper tubing fairly safe?

Thanks.

--Art