I believe "Sunningdale rules" means playing straight up, no strokes, even when handicaps differ. But for any hole where a player is 2-down or worse he gets a stroke.
I almost always suggest that game in lieu of normal stroke assignment. If the handicaps are within 4-5 strokes of each other it almost guarantees a match that comes down to the last couple holes even if one player or the other is having a very good or very bad round.
It also tends to assure that the better player will win the majority of the time when there is, say, an eight or ten stroke difference. Which I think is eminently fair. But it will let the weaker player in the case at least hang around and not get beaten seven and five or some such.
My long-hitting buddy Mark and I play "Sunningdale rules" when we get together. He plays two sets of tee farther back than I do because he drives the ball about 260-280 versus my 200-210. But since his handicap is about ten strokes better than mine, even with me playing forward so far his gross score will be lower. We have an uncanny knack for every match coming down to a putt on the final hole under that arrangement.