SxS will vary in POI side to side. The spread is wider with hard shot than lead shot. People generally want one barrel tight and sight in for that barrel. The other they choke open and let the spread account for the barrel being off. With a .410 you don't really have enough shot for that open barrel. Maybe Fox Trot's 1oz load, but... I'd look at 28 gauge minumum.
On an O/U your spread is vertical. Aim at head dead on with top barrel and the bottom will strike in the neck. No problem. Yildiz .410 is on a baby frame. Their 28ga in on the 20ga frame. No point in the 28ga when they sell a short 20ga of the same weight.
As for quality of Yildiz, I've had good luck with three. The first had a couple of problems but being able to drop it off and pick it up at the Academy gun counter for repair shipping is unbeatable.
My main turkey killer is a 20ga Yildiz O/U. Has been for about eight years. I have loads of confidence in that gun. I have not had a bird escape that gun. The past few years I have killed most birds with a Yildiz single barrel .410. I like it a lot, but it is easy to miss with. A .410 double would be the similar due to the overall size of the pattern and lack of shot for opening the core of the pattern.
If I didn't already have the 20ga and the single .410 I'd be looking at a 5# 28ga O/U.