@Scrumbag
I have a 2.5x (pretty close to 1.8 I would imagine). At 25 yards on a standing or walking animal, I think its OK - full but OK. I've finished off a buck deer before who stood up again in a thicket 10 feet away from me --- total brown blur.
Like your cheek weld concern, personally, I think having 1 sight system is the way to go. If you are a scope person, take your chances with a 1x. If you prefer red dot or iron sights, know your limitations. Yes you could "plan" on removing your scope after the first shot, but its also very likely you could drop/stun a buffalo, make a quick reposition, and he stands up again right in front of you.
I will not go on a buffalo hunt until my daughter is grown, but I plan to only use Iron sights.