[I will not promote] Initial Sole Director (co-founder can join later) widely accepted ?

So I have this dilemma. We are two co-founders. However, we want to make it the case that when I accepted to YC, only one stays on the board till the first institutional priced-equity or something like that, then the second founder joins. Is this an accepted practice, and common ? I checked this blog post "splitting-equity-among-founders" on YC, and it mentions by the end that a CEO only on the board initially before major funding is recommended. I am really interested to hear the different views on this.