I prefer to have my guys on the corner right next to the left side of the arch, they all face out and then I pull Eck and bring him and tank him facing away from the group he is right next to them so not much chance of him pouncing on them and if he does I can pick him up right away. Real easy that way he goes down like a sack of potatoes, I can one shot most of them, I might have an issue with the Colossus some of the times but for the most part had Gun on farm for a while.
Glad to hear you are doing better, its always about learning the fights and after a little bit they just become second nature.