I think it requires a certain viscosity of oil.I've been wet shaving for 5 - 6 years (don't remember exactly) and have never really used much in the way of pre-shave products. Early on, I tried Noxema, but never really noticed a difference.
Recently, Village Barber shave oil was recommended as a product that "somehow" helped mow down the more stubborn whiskers.
I bought a bottle, and used it today. With a shaving cream (Mr. Taylor), Razor (BBS1) and Blade (GSB) that I've used may times, I found that using the oil as a pre-shave gave me the BEST shave I've had.
After just one shave, this will be part of my den and routine for the forseeable future.
I have tried baby oil but it just doesn't do much for the shaves, for instance.
I am thinking a mixture of castor and jojoba, or lanolin oil, would be ideal.