I think Buddy has the right "thoughts" on this. I feel it means more to the person tying the flies than it does to the fish. The only comment I can make is that I feel that it would make more of a difference on a dry fly pattern than any other pattern because on very small dry flies the weight of the tippet on a down turned eye hook would have a tendency to pull the front of the dry fly down and would affect the floatation of the dry fly.

If your question is will the angle of the hook eye affect the hook-up ratio, I do not think so, but, I do feel that a long shank hook provides the fish a better chance to dislodge the hook while fighting. It makes little difference if the fish is lip hooked, but, if the hook point is past the lip and half of the hook shank with the hook eye is protruding from the fish's mouth, than the long shank of the hook provides the fish a lever to assist with unhooking the hook when pressure is applied at an angle during the fight. With shorter hook shanks, the tippet is against the fish's mouth and will not provide a lever. Just my thoughts and nothing more....