Oil Pressure

[A666K@aol.com]

Two questions:
A. When attaching an oil pressure gauge to a car (say a spitfire?!), which is 
preferable 
  I. a sender on the block with wires to an electric gauge, or
  II. an oil line to the gauge itself (mechanical type) 
  What are the dis/advantage of each design.
B. If I was to go with a mechanical type gauge, where could a tap a line, 
assuming         that I want to retain the external oil line and oil lamp.
TIA,
Avi