Re Rubio Monocoat - Monocoat sticks only to bare wood, not to other finishes, including itself. That's why it is a mono-coat finish. It is, however, a two-part finish - oil and activator. With the activator, the finish is cured enough for light use within 36 hours; otherwise the cure takes much longer. I have only used it on raw wood; it provides an excellent matte finish that is reputed to be hard-wearing; touch-ups are super-easy. Using it to refinish anything seems more chancy, because all traces of the original finish must first be removed. For more information, see this blog post & the follow-up comments.
-- Jim
Use the right tool for the job.