Cool, so headlights are all sorted. The bullet connections are fine so long as they are clean and corrosion free. There are various methods people use to prevent corrosion from petroleum gel, contact cleaner and recently this stuff has become available : http://www.12voltpla...r-25g-tube.html
Yes oil pressure light circuit is simple, live with the ignition, through the lamp to the switch. If there is no power at the white and brown connection to the switch then suspect the lamp. Assume it's the gauges behind the steering wheel ?? Carefully pull the cover off the front, the clips are likely to be very stiff and difficult to get cover away cleanly. Then you will see two screws on either side and another hidden on the top, remove the screws and gently pull the instruments forward. There is a multi-plug for the electrics and the speedo cable connecting the instruments. The lamp holders are on the back, quarter turn jobs with a miniature wedge base lamp in each.
You're getting there nicely.
Phil.