Hi Somerset,
Yes, 3/32" will work fine for oil lines if the I.D. is about 1/16". The K&S 3/32" copper tube works fine for oil lines. This is what I used on my Super Simplex. There are no provisions for oil line placement in the drawings, so, you have to use your own imagination. Although the general arrangement shows oil boxes on the front side of the water tanks,
I used small oil cups mounted between the boiler and running boards. A separate cup for each main bearing and one to drip oil into a cup on the axle pump eccentric. The difficult bearings to get to are the ones under the fire box. I mounted oil cups for these in the cab, making the oil lines a bit simpler than if they came from a cup further forward on the loco. In the bottom of each cup is a small punching of wool felt, this keeps the oil from running all out of the pipe. Once the pipe is filled with oil, two drops in the cup will cause two drops out of the end of the pipe. Gravity feed works fine. The pipe should protrude a bit from the inside bottom face of the horn block, otherwise the oil will go everywhere rather than dripping into the "cup" on the top of the axle block.
If you make a "box" rather than cups, make a separate oil cavity for each delivery. That way you can know if each line is delivering oil. If it is one large reservoir in the box, you will not know if some lines are delivering more or less than another.
I am in the process of painting my loco this winter. Part of the painting project is to finish some of the last details, this includes creating a formal oil system. I hope the photos will help suggest a solution for you.



Edited By David Wasson on 10/01/2019 00:29:16