1. Un-equip trap builder's gears at the tavern in order to place gas traps near crystals as possible. (Place gas trap at south side of upper tier crystal and north side of lower tier crystal).
2. Apprentice -->EV -->Huntress -->Monk -->Summoner.
3. Stack 3 DSTs and 4 LTs as demonstrated at lower tier non-aggro square.  Place a Magic Blokade wherever you like.  It's just for DU bonus. I place it at Hint 1 to prevent my AFK summoner from getting pushed off the edge. you can replace it with any 1DU unit such as reflect.
4. Place two 6DU and one 4DU buff beams as demonstrated. 6DUs are for the minions/traps and 4DU is for LTs/DSTs. PLACE 4 temporary 4DU buff beams at Hint 2 for Prox-mine traps later. Place two 1DU Reflects at non-aggro square.
5. Place 2 Gas traps as no. 1 described. After Gas traps are done, gear up Huntress. Place four Prox-mine traps as far out as possible at Hint 2.  MAKE SURE all 4 prox-mine traps touch the ends of corresponding 6DU buff beams. Sell 4 extra buff beams.
6. Stack Auras at north side of upper/lower crystals.
7. Place minions on 6DU buff beams. More powerful your DST/LTs are, less archers you need. NOTE! minions must be as close to the edges as possible, or the ogres might hit crystals during combat phase.
8. All other AFK characters stay at non-aggro square. I like to put a flash heal summoner at Hint1.
9. Upgrade buff beams --> Prox-mine traps --> Auras (especially strength drain) --> DSTs/LTs --> Minions.
10. Check Traps/Auras health from time to time and flash heal.

Note: I started this build when my average stats were nearly 3000, more or less. Use 4 Gas trap configuration instead of 4 TNT trap if your stat is too low, and that gives you 6DU + 1 extra DU. So you can stack 1 more LT. Killing ogres or djinns not fast enough will cause serious problems. You need Gas traps to stop djinns or littile mobs threats.

Here is the Video