Adding extra summoners does increase the amount of mobs per wave (good thing), but it also increases their health (bad thing). The increase in health means it takes longer to kill the mobs, which makes the drops per hour slower. This is generally why adding more than 2 summoners is not recommended. I'd recommend more than two summoners in certain situations. One such situation is AFKing with this build.
For this build if you don't AFK, 2 is the optimal number with just using guardian summoners on the tower stacks. But if you do AFK, then the 2 summoners with the auto-repair pets are needed to keep the aura health up. If choosing to AFK with the auto-repair summoners, then having the guardian summoners as well would be good as they do add a significant amount of damage that the towers output, which will negate the extra mob hp from adding them.
Thanks for the clarification!
One more improvement to the built for lower stats: You don't really need the reflective beam on the far left of the setup. You can instead put in on the stairs to further protect the ogres if they're suffering a lot of damage.
04 August 2020
I believe the amount of armor dropped doesn't increase from 3 to 4 players, so wouldn't adding one just make it harder without any positive addition?
25 August 2020
Adding extra summoners does increase the amount of mobs per wave (good thing), but it also increases their health (bad thing). The increase in health means it takes longer to kill the mobs, which makes the drops per hour slower. This is generally why adding more than 2 summoners is not recommended. I'd recommend more than two summoners in certain situations. One such situation is AFKing with this build. For this build if you don't AFK, 2 is the optimal number with just using guardian summoners on the tower stacks. But if you do AFK, then the 2 summoners with the auto-repair pets are needed to keep the aura health up. If choosing to AFK with the auto-repair summoners, then having the guardian summoners as well would be good as they do add a significant amount of damage that the towers output, which will negate the extra mob hp from adding them.
25 August 2020
Thanks for the clarification! One more improvement to the built for lower stats: You don't really need the reflective beam on the far left of the setup. You can instead put in on the stairs to further protect the ogres if they're suffering a lot of damage.