When I spray McLube Sailkote on my slugs (~43' luff length) the sail seems (well almost anyway) to just want to fly up on its own with just hand pulling on my halyard. And the effect of spraying the lubricant is quite long lasting.
An alternative, but not nearly as good, is dry silicone based spray lubricant from your local hardware store. I've found that it's not as effective as McLube, but a great improvement over nothing. The hardware store dry silicone spray does dry gunk free.
I agree with the other responses--- don't use anything petroleum based. Dust and gunk will accumulate that will thicken/gel in the mast track. And over short order cause more resistance than doing nothing. ... Not to mention the staining to your mast and sails and possible damage to the finish. Visualize your garage floor back in the days when dripping oil from a car's oil pan or crankshaft bearings was the norm.
Just an aside on the ease of raising sail topic. In case you don't do it, when the sail is raised, the boom angle should be set higher than the mainsail's natural hang level by either using the topping lift; or by extending the rigid boom vang if that's your setup. To achieve this, also slacken the downward tension of the mainsheet and boom vang. Without the boom raised, the weight of the boom is transferred to the mast slugs pulling out away from the mast in the slug track (i.e. the aft direction) = a lot more friction. After the sail is raised and the halyard tensioned ,then you can let the boom hang to it's natural level for the sail trim conditions you want/need.
