Top is the two frame method, bottom is the drop shadow effect.
Bottom effect has no size, spread, noise. 100% opacity, 40% k fill. Because it is not a vector effect, zooming in beyond the 100% or so zoom level, it will show pixelation. Next screen shot is the bottom of the two frame method, top of the effect method zoomed way in...
If this is for print, the effect version will be fine.
But if you want to use the two frame method, just us the transform panel to move one to a position that looks good to you, make note of the vertical/horiz offset, and apply it consistently to each set of frames you want the look and then group the frames so they cannot be accidently seperated.