I am in the middle of doing my large staircase too. It was all golden 90s oak. Stairs have 18 year old builder grade beige carpet. I counted the spindles tonight, 63, and the steps are all open to the outside, 1/2 on both sides (which means a tougher job). I had no idea what I was doing, just read reports on Pinintrest, etc. And I am no spring chicken, I am 54. I never stripped or stained anything in my life! I have been meaning to blog about it, I am about 4 weeks in. Still on the railings and spindles. I am going to a dark brown, with a slight red color. White spindles. Add to the work, many spindles were chewed by my dogs when they were puppies. (ARGHHH!!)
I wanted to blog it, because I am using ALL water based products.... all the reports I read used oil based, including the gel. I will say, you will likely find surprises under carpet. Not good ones. If you have a landing, like I do, that is another headache (I am passing that over to DH, who is not thrilled to have to figure it out). And I got lucky, there is hardwood on the steps, with bullnose. When they put carpet on, they staple and tack the heck out of it. I am not sure how much I have spent on supplies, more than I needed, because I tried many different techniques as I learned. But mostly this project takes TIME and more TIME. (but I have a huge staircase, for most people it would be 1/2 as much work).
PS, when you paint round spindles, use a FOAM brush. I need to blog, I have many little tips, now that I think about it.