I use RCBS spray lube (Case Slick), as well, and haven't stuck a case with it yet. My technique consists of the following:
- Dump two to three handfuls of cases into an Akro bin, so that they all lay flat in the bin, single-layer
- Spritz case lube over them, about 4-5 pumps.
- Shake the bin to roll the cases around
- Dump them into case feeder hopper
- Repeat 3 to 4 times, not overloading the case feeder
While they tumble around in the case feeder, the lube gets even more distributed. Every once in a great while, I will feel a case getting pretty tight in the sizing die. At that point, I back it out, and run it up again. 99% of the time, that takes care of it. And that's the important part: feel how the case is going in to the sizing die, and know when too much force is too much. When you feel that, stop - don't try and muscle through it, because that's when the case will stick.