Same here, I have a bubble level that fits into the hot shoe but that does not help me when looking in the viewfinder. When I do upgrade to the 80D, it will have an electronic level in the viewfinder that should help eliminate that problem for me.
The first picture was actually more tilted, I tried to correct it as much as I could without cutting the top of the tower off, I may try to retake that shot but stand a little further back and try to focus on leveling it more.