My stairs are stripped of carpet and ready for install of oak tread and riser. Though, I first need to install the side trim for the inside stringers, then cut the tread and risers to width. I plan to paint the trim, therefore, I don't need to use oak or any other expensive wood. My first thought was Poplar but even considering Prime grade Pine. What are suggestions for the type of wood to use and the best thickness?
Thank you