No problem. My horses have a pretty big steep hill in theirs. I'm not positive if I have a pic, I'll look and if I do I'll attach it.
But anyway, we used to block it off but last year I think was the first year we didn't. Either that or the year before. (Sad how I can't remember lol) But anyway, they made their own judgment of when they could and couldn't go up. When we got too much snow they quit going up. The first few inches they were still going and were fine, then after we got more they quit as there was nothing up there for them anyway. Chances are your horse will be okay with the hill but I'd still do the Vaseline anyway. I did.
So, I did find a couple of pictures. They aren't very good though. It's tough to get a good pic of the hill. Haha if I find a better one later I'll post it. But anyway, you can see the basics.
The middle one is Hunter on top of the hill. You can see the peak of the barn in it. And for reference of how big the barn is I posted a pic of it. (It's very old :) But I like it!)