QUICK NOTE: If you're lazy, the "tl;dr"s explain most of the info you might need.

Overview + Tips
tl;dr: If stats are ~2k, you can afk the build easily. Make tha aura pairs touch, put the buff beams at the back of the auras, put the lightning towers at the back of the buff beams, and put the traps at the front of the buff beams.
Nothing about this build is precise. It's meant for people with lower stats to throw something down and see results without having to repair. The only thing that you need to figure out is how much to upgrade. If you have lower stats, it may be important to max everything, but others may not upgrade anything at all. If your health stats are ~2k, you can likely AFK this for the entire game after upping only buff beams.
The exact build is not important. Just make sure that the aura pairs touch in the middle, the buff beams start from the back of the auras towards the mobs, the lightnings are at the back of the buff beams, and the traps are at the front of the buff beams.

Mana Stuff
tl;dr: If you wanna summon and afk for the full game, start on wave 10.
If you're starting from wave 1-8, summon auras, buff beams, infernos, and one lightning tower for every side that will have two. You'll get plenty of mana to finish the build in the next build wave.
On wave 9, you'll be 80 mana short of summoning everything on the first round. Leaving out two proximity traps rounds it out pretty nicely.
On wave 10 and over, you can just summon everything on the first build phase.

Stats
tl;dr: You can use this run with very low stats if you add 7-8 archers per side. (I used avg. spread: 800 1.6k 800 950 and it worked well.) 
I was able to clear the map with pretty low stats using this build while only upgrading the buff beams. (Average stat spread: 627-988 Tower Health, 1411-1881 Tower Damage, 650- 878 Tower Range, 698-1175 Tower Attack Rate) Take note, though  that you can add 15 archers to each side, which will add a lot of damage just for the dark elf warriors, making the run a piece of cake.

Misc.
The build will work for any difficulty, but I don't recommend it for any other difficulty than Nightmare, seeing that the mobs go significantly slower on lower difficulties, and this build is made to summon quickly, not so much to kill the mobs immediately.
The XP and Time (64,000,000 and 1:10:00) are from wave 1 to wave 35.