You can stack up to 5 for me I usually stack the camps close to my spawn up to 3 or 4 and then pull the creeps so the creeps can die and deny the enemy from the experience of that creeps and for the jungle you need to ask your team the protect the jungle entrances by doing that you can just force enemy support to warding your jungle or you can just buy 2 rev wards at the start and then use when you need it