Per Mossberg, they specify to lube it very lightly; especially in the Gas Piston area where the spent gas are exhausted.
I like to keep my firearm's bolt area more on the wet shine, but not dripping or runny. The trigger group area, I used a teflon dry lube spray...goes on wet, then dries with a white coat of teflon. I'm one of those, that will do a detail clean and lube after every shooting outting...even if I only shoot 25 rounds. I'm a big fan of Breakfree CLP and Militech lubes.
Since I just got my SPX..I will have to experiment on how much and types of lube..which depend on how dirty the ammo shoots.