Can 11 Towers Defend Two Gates in Soulkeep?

In this level I have faced 5 fierce waves of level 5 and I can pass them all although I have lost some hearts in wave 4 as I have made a mistake using mana to add more towers and not to upgrade main one like card sharp that are first line of defense against Fiends.

In this level I have passed 5 waves and reached wave 6 which was so hard that fiends come in large numbers and this was not only the problem in as they are entering the map together this means that you may face more than 50 fiend at the same time so back to my question in the title of the post can 11 towers defend the gate and this is what I calculated.

In this case I need every tower to kill 5 fiends in nearly the same time or few seconds so I have used my spells which did a good attack to fiends but at all the managed to enter the gate as I have said that I was with 1 heart only in wave 6 and this is make fiends mission easier to enter the gate.

What I have used is fountain of terror and card sharp and I used them all to make those 11 towers that are in all the map but as I have said they will not eliminate fiends with their current power as I need in just few seconds from every tower to eliminate 4 or 5 fiends so I need to focus on upgrading them as every upgraded tower will have the hitting power of two normal ones.

For new fiends such as Crystal hand I managed to kill them all and gathered a good mana from them as I have reached wave 6 with more than 400 Mana so I need to upgrade towers and see if I can pass this wave.