Yeah, I've used that riser calculator... a lot. But until I actually get the seats (Berkline 088), I don't know exactly how high the tops of heads will be. I also don't know exactly how far back the 2nd row needs to be in order to recline. I've done a lot of experimenting using "dummy chairs & props" with the screen only 24" from the floor. I think 29" will work fine, but I won't know until for sure until after I spend the money!