I've had CleanupLifetimeDeadPlayer set to 3600 (1 hour) and currently 7200 (2 hours) due to players saying when they run directly back to their body that it's not there. I personally tested this myself via in-game suicide. My tme was around 1:53pm est and the body was gone by 2:33pm est.
Not sure if there is another setting I need to adjust, but this setting is not working as intended.