Looking for stairway advice

Question

I am not sure how to tie in the rails where I have existing trim. Also I want to go up the stairs And find this part a little scary, all different angles etc.I am planning to do this in my hallway on the first and second level.Since my ceiling height is 9 feet, below the light switch, that would bring me out about the halfway point which I was told looks awkward. So I guess I have to go above the light plates so that it’s a little weighty on the bottom? I have already created a grid wall in my dining room. I am going to create rails with a horizontal cross rail about a foot below the top. Just trying to plan it out before I go. I will be using pre-primed MDF boards that are just under 3 inches wide. I think they are for doors. Should the top rail be bigger than the other rails. Rather than remove the baseboard I will probably just try to find a moulding I can add to it so there is no overhang. Thoughts? Appreciate any advice.

Nicki Petruzzella Kerns · Answer

I think it would work if you're careful with placement. Can you make the rail at the top of your battens start at the corner of the moulding in the above photo? Place one of the battens directly underneath the vertical moulding here and you should be okay.