I don't know how your first rapid fire is drilled, but what I like to do when drilling two of the same balls is place the pin up/down a couple inches from where the original ball was drilled.  For example, if your first rapid fire was drilled pin over bridge, then the second one I would drill pin under bridge and maybe lightly touch the surface with a scotch brite/abralon pad.  The pin down ball will pick the lane up a bit earlier and be better for smoothing out the fresher conditions.  Once the lanes begin to transition and your pin down ball is not getting back to the pocket (i.e. struggling through the carrydown), you can switch to the pin up ball and open up the lane more (i.e. get the ball to read the back part of the lane more).  I am getting a rapid fire in a couple weeks, I'm really looking forward to throwing this one, looks real good.  Good luck.