This is all speculative and based on what I heard in the last CC, but he seemed to think it was a fairly quick process, something to the tune of 10 days if I remember correcly.  I have never been part of an uplisting stock so I am learning the process as well.  

I didn't start investing in OTC stocks until last August.  I mostly invested in a few Dow and Nasdaq stocks.  I only decided to give these riskier stocks a try once I started seeing big businesses get relegated.