Just followed you. I am running a slower rig with (6) 1060 cards mining ETH. Getting about 125 Mh/s in a reliable form. Recent prices make that work out to around $140 to $150 a month before electrical costs. I am probably at a 2 year break even point too.
The only things you can do that you probably already know is lower your power use and overclock. I like the idea of your outdoor box. I could stand to run a similar setup since it has become summertime in my area and my rig is like running a small space heater in my condo. If I could put it somewhere like my 2nd floor patio in a box with the fans running, I could avoid the interior heat like you are. The noise wouldn't even be an issue from my running the added cooling fans built onto the rig that I don't even use. I will track your progress. I'm running EthOS but am considering other solutions myself. I know I got into the mining scene too late. I am actually mining now to take that ETH and convert it to STEEM to build up this account.