Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Bonjour,
To my opinion, the angle does not matter except the fact that the oil above the steam pipe will flow quickly.
If you operate at about 30 PSI (2 Bar) the steam is said "saturated" with water which is lubricant.
So, you have just to manage the needle valve to have the content enough for all your operation.
Important, I commonly use grade 400/500 steam oil (1 000 for scale 1 machines), a thinner oil would be consumed too quickly.