ive been runing this a while and here are some things you may or may not care to note.
first wave if you get all chests you can do everything but lsts and 1 dst i do the one facing north that is easy to build in wave. or all north for 1 golem and 1 lst and all monk+ev things
during boss wave if you have a ev beamer right next to the wall and golem both squire and barb sit right by each other for a simple beam leaving ONLY spider queen for the sweep.
sometimes during waves 11-13 a lighing archer or goblin will go attack south crystal sometimes if you are running this afk.
if you fail to kill the bosses quick enough a lightning res goblin or archer again will attack south core but that takes some time like a minute.
a rodoulph monk will attack your towers if you dont kill boss in like 20 seconds so you need to go kill it.
I afk rounds 9-13 with just a app or a app and monk+hunt summoner on dsts on ruthless as this build is quite sturdy.
also if you are running it afk you can set a 10 minute timer right after you get into combat wave for wave 9 and it will end at like the end of wave 12 or the start of 13.