Aura stack in the north between the Crystal and the Forge
Aura stack in the south in the fire pit or on the crates (depending on the point at which the auras no longer overlap)
Traps
Gas Trap above forge, on the ramparts, unequip all gear from your Huntress builder, if you can't build the trap in the north because of the crystal. Don't forget to put your gear back on after you've set the trap, and upgrade the trap once so it can hold more than three charges.
Gas Trap south near the edge / crates
Proximity mine in the center of the black circle on the ground
Hint 2
Holy Bulwark can block both paths when placed like shown
Hint 3
Buffbeam 6DU max length
Safespot - no TB needet, 2x Apprentice Guadian and 2x Huntress Guardian (2x Summoner) is enough.
i do this semi-afk with 4 Summoners, 3th one has 2 dps pets (just for fun, not required) and the 4th one is my Heal and "runner" so i can pick up chests during waves
Using Flash Heal once around the middle of the wave and once at the end is usually enough