Although this is for non high stats, you still need decent stats for this. I'd say 6.5k-7k main stats for hardcore, but might be able to go lower. Over 7k definitely makes it smoother, over 9k you can probably go with a faster build xD. This build aims to be relatively safe and making the boss fight as easy as possible. The boss is actually the easiest part of this build. This build does work on ruthless with high stats, but you need 2 tower boost monk, one for each side, when super wyverns start spawning like crazy (the last 2 waves). You can replace one of the tb by a mana bomb apprentice to clear super wyverns. You can even replace both, but I like to keep one for tb/hb for the boss. 

Note: I have not tried ruthless yet. It might work, or not, may or may not require different stats.

Building and Combat phases

I start the map on the west side, grab all the chests there. Build auras, 1 gas trap, the buff beam, and 1 reflect for spider queen. Then move to the east side with the carpet. Pick up all chests on the houses, then those on the ground. There, build the auras, all the 3 traps, the buff beam, and 1 reflect (in front, for spider queen). Move all the way to the south core (the boss area), and build the aura stack, the 5 DU physical beam, and the 5 DU buff beam. Make sure the wall is being buffed if you wall often dies there. With the remaining mana, you should have enough for a gas trap south. You can then start the wave. You should have plenty of time to build all of this.

For the first wave, start west with an upgrade jester. Max upgrade the buff beam and throw a couple of upgrades on auras and gas trap, then hop on the carpet to get to the east side. There, do the same. At the end of the wave, there should only be wyverns on that side. If you've got a stuck mob near the auras, you can take advantage of that and max upgrade everything (this happens a lot on wave 2 with a stuck ogre). Make sure you end the wave with max mana, and you can even leave a mana stack near you to make sure you have enough mana during the build phase. 

For the build phase after wave 1, time is a bit tighter, but nothing too bad. You should be in the east part when the build phase starts. Switch to summoner and build the spider queen and the first minion stack behind (2 mages, 7 archers). Toggle out of overlord mode to pick up the mana stack you left near you, and back in overlord mode to build the minions west (point 1), then build the minions south. Those minions help with the djinns there on wave 2. After this, switch to EV and place the 2 missing reflects west, then go all the way east. Over there build the 3 reflects around the minion stack. Switch the huntress and place the proximity trap and inferno. After this, there shouldn't be much time left, so you can swap to upgrader Jester and start the wave.

For the second wave, you can upgrade stuff west. Keep an eye on the south core, and don't forget to upgrade stuff over there. From here you can do pretty much what you want. Upgrade minion stack, spider queen, etc. 

For the build phase after wave 2, finish the build with towers south and reflects. All you have to do from now is just upgrade stuff, or sit on a tower boost monk east and/or west until the boss. Upgrading the towers helps to kill the boss faster. 

Boss Fight

The final wave is actually harder than the boss itself with this build. With more characters (assuming you're splitting) the wave is harder and longer. You can bring a tower boost monk and/or initiate boost monk. Having both is safer and will decimate boss, but you could technically do with just a tower boost monk. Also possible without a tower boost monk, but more risky. For the boss, just boost or double boost, and towers should kill him pretty fast. Make sure to keep your characters behind the physical wall so they don't get hit by the boss and lose their hero abilities.