I started with M4tt's summoner build, but his stats are likely better then mine, so I had difficulty and needed to modify the build as I went; but still special thanks to him for the intial build.  I do 2 Lighting Tower stacks of 6.  Both boosted by Monk/Huntress guardians on 2 AFK summoners.  (and if you want, 2 is enough) 

The third summoner is an upgrader/roamer/flash healer.  Equip this summoner with an attack pet and a genie, so he can roam, collect mana and upgrade.  Once all upgrades are accomplished, switch the genie out for an additional attack pet (or crystal core if something took damage).  I start on wave 23, so I get all three of the map's pets (Guardians, Harpoons, and Deadly Strikers).  Always add an addtional player after the start of wave 24 and 29 (then drop out after the wave finishes.  I also add in a Tower Boost monk on wave 35, just to finish strong (and ensure I get at least one roll on an Ace of Spades in the final loot).   I prefer this map to Infested Ruins (probably just because of burnout).  The pets always sell well in an AFK shop.

First wave (or 2) definetly upgrade everything, maybe use a Upgrade Jester at this point, or other strong upgrader, then drop them for the roaming summoner.  The wall of minions is only there to keep mobs off the tower stacks.  It can be almost any combination of minions you want, just bodies in the way is what we are after.  

Note 1: 6 LTs stacked

Note 2: 6 LTs stacked

Note 3: Minion mob to keep enemies from tracking to the stacks, should cover from the top of the bottom stairs to the bottom of the mid stairs, north of the west-most pillar...if that makes sense, can use WAY less than all 140 if you want, they just need to be a decently self sustained wall.  I also boost them.  The boost beam under them should touch the south-most strength drain aura and Ethereal Spike Trap.

Note 4:  Boost beam should touch the gas trap and darkenss trap.