I really only find spray lube handy for lubing derailleurs and shifter internals. Don't like using it anywhere else because of the overspray.
Oil spreads itself into spaces where it's needed, so a drip bottle is all I use most of the time.
If your chain has any signs of rust you:
a) aren't lubing often enough or b) aren't using the right oil for your conditions. Rust should never be tolerated. It's steel biodegrading into dirt.
If it's wet, I like using a thicker oil like Phil's Tenacious. Doesn't get washed away so easily. Tri-flow is great for dry conditions.