Amount of Wood

I'd start with less.. let's say half that amount. You can always up the quantity for later cooks.. but, if this cook has too much smoke it's difficult to remove it.. and half that amount will provide very nice smoke flavor.

2-3 oz is likely plenty and I typically only use 2 for my ribs and about the same for poultry. In fact.. I can't think of anything I use more than 2 oz for.

Another thought. Both woods are very good and might work very well for your purpose.. but, if you don't konw the difference at the moment, why not try one wood, say 2 oz of Apple and see how you like it.. then try Hickory next time. Keep good notes... both cook and product.. be sure to include your wife's comments on both.. if you know what's good for you

Louie-Q
I smoke baby backs all the time. I usually hang them with the rib hooks, but doing 2 racks just lay them on a rack. I usually use 3 to 4 oz. of wood, but being from No. LA and almost East TX we like a lot of smoke!! I use mostly hickory with a some cherry, or apple. I usually use 2/3; 1/3. I also use the AmeriQue. Good luck