I've really thought of it more like "three guards / two bigs" - though that's also somewhat reductionist, because it's frequently situational and based on matchups. I doubt Pikiell/staff have rigid definitions of any of the positions, and see it much more fluid in terms of what they're trying to accomplish on offense/defense.
That "wing" player or "small forward" or whatever you want to call it usually needs to be able to guard a forward, though, defensively. So that normally means a bigger guard, 6-5 or better.
In our offense, we really have had two guys who have played that position the last two years - Thiam and Williams. Thiam isn't a great ball handler, so has mostly played off the ball looking for catch-and-shoot opportunities (though he's started to expand his repertoire a bit). Williams handled the ball more, but when he was the third guard on the court he was frequently found crashing the boards and looking for offensive putbacks among the trees.
Adding Mathis and Kiss next year will mix things up. Mathis is 6-4 and Kiss is 6-5 - so they both have the height to guard wing players - but they're also both used to being the second guard in offenses, rather than the third. Will be interesting to see how Pikiell incorporates them.