Hello again Eugenie,
I got a little focused on part of the question, but failed to answer the main part which was, "How long will it take top find someone to rent?". The answer is simple; the amount of time it takes to find a tenant is commensurate with the amount of rent and more precisely the percentage of the current market rate that you ask for rent. If the "Fair" market rent is $850 per month, and you ask $900, you may never rent it. If you ask $825, it will likely rent within a few days of hitting the market. "Fair market" is determined by a number of factors, including:
Location (which includes shopping , schools, transportation), neighborhood amenities (such as pool, spa, workout room, etc.) and unit amenities (such as microwave, appliances, closet space, etc.), size, and condition.
Of course this also depends on how you expose your condo to the market. If you put flyers on telephone poles, don't count on much result. If you use Craig's list, or a property manager, it will rent fairly quickly.
So, to recap, if you are over market, it could take weeks or months.... and that is rent you will never recover. If you charge slightly under fair market, it should rent within days.
Best wishes, and thanks for reading.