The wood stair treads are 1" and will have 1" overhang over the plywood treads. The inner string that you see screwed into the wall my husband ripped from high density mdf. He left it long so he can trim it later. He counter sunk the screws so he can fill, sand and paint.
Now we are figuring out how we want to place the newel posts and determine the angle of the divided landing steps before we order all of the stair parts. We are thinking of going with knotty alder treads and railing stained dark (this is what our cabinets are). Our floor is hickory and hickory stair treads look nothing like our floor so instead of trying to match the floor we are going to go obviously different so it looks on purpose. There is a dark color in our floor that goes with our cabinets and that was why we picked the floor so it should look really good.
Don't look at the and handrail, he just moved it up when he was working on te stairs to give us something to hold on to. He is taking it down before he does the wainscoting.