edit: ive made a few minor optimizations compared to what is shown in the video, shown in these screenshots. https://imgur.com/a/2Rav29i
basically i angle one of the mortars a bit further to the right so it can see deeper into an angle i noticed enemies sneaking through, i swapped the placements of the wisps in the mortars compared to the video so the mortars can see deeper towards the crystals which resulted in faster times, and then i swapped from an apprentice/squire guardian summoner to a squire builder and i sit him off onto the train tracks on the far left side of the map so he cant be targeted + i get to stare at the void which results in higher fps and generally faster times. 

if your tb monk is dying swap to SL skin for the extra hp(this didnt use to happen but many tower nerfs made the evs start getting cleared slower im sure u can maybe place an extra ogre infront of him or something but i havent really tested that) 

setup the entire build in the build phase, the mage is placed under the moving gear on top of some rocks so he cannot be hit and killed
w22 upgrader, tower booster, 2 summoners both with 1 huntress guardian and 1 monk guardian each boosting 1 stack

if you have finished upgrading swap from your upgrader into your squire/guardian builder(i think i prefer squire after a bit of testing, times are pretty much the same but i think buffing the mortars is safer for crystal defense)

video of the build setup and first wave here: https://www.youtube.com/watch?v=Tk-hikqzbx8