Wow. This would be 4 pages on Enos by now. I am in no way an expert, but I have been going through this as well. The 90 degree option is really only for a C-More, so let's look at the optics first. Close to 90% of the registered open shooters at the Nationals are running C-More sights. The rest are a smattering of Delta Points and other lower profile optics. I prefer a 90 degree mount but the guys at the top are running regular mounts with a C-More (except for KC, but he can shoot anything). Now, that's what they are doing, I have a 90 degree C-More on my open gun and a good friend of mine runs a Delta Point, and another friend runs a standard mount. I think I could get used to any of them with a little practice. My biggest reasons for the C-More with a 90 was two fold. First, it was less of a transition from irons and second, you don't have to worry about mechanical offset as much. My advice is to look through a few.
From a dot perpective, I like the 6 minute I am running but that 8 is sure easy to pick up. The DP has a 7.5moa triangle that works great too. On my 3-gun pistol I am running a Trijicon RMR with a 3.5 minute dot and it works fine. Again, all personal preference.
Hope this helps a little.
