BL Savage woes.......

Okay, I've had a pretty good experience with the shocks on both this truck and my buggy, but don't really have the time today to tear them down and change the oil. So what springs and wt. oil do you suggest? It's got some kind of chrome ones on the front and whites on the rear, and a fair amount of preload.....I'd be afraid that with heavier oil the springs wouldn't extend again.