I have a single case with 4.7s, I have no problems getting around the hard spots (con, jungle, whatnot).  Crawling with an auto is so nice.  When I had the 22RE, I always wanted dual cases, but since the swap, I have simply not needed them.  This is Marlins site so your gonna get a lot of opinions.  If you got them, install them.  If you don't then you can always do it later.  With a 4.3 CPI/TPI your gonna almost double in power