a Profoto D4 2400ws Pack with heads. I use this set-up all the time for Product shots. BTW I use just two heads (my personal style), but the pack will support four heads. BTW if you don't use something three time a week, it is better, less expensive to rent. I own little, except a light meter, and rent what is needed by the job. YMMV.
With the D4 you can adjust each channel by 1/10 stop. Makes it a lot easier to get perfect exposure. Go to http://media.profoto.com/pages/search.php?search=!collection34
and click-on D4 Users Guide EN
to down-load a PDF.
Three things. Angle of incidence = angle of reflectance. This means that you can lose a reflection by moving the light up-down / left-right a few inches/feet. The second is shoot at f/8 to f/16 DO, NOT worry too much about diffraction. I use a 5D3 with a 90mm f/2.8 Tilt & Shift and f/16 is not a problem. Third you need to use a tripod.
Also shooting tethered is best. I use Capture One Pro, but Canon has a tethering program. Shoot a shot, then look at your computer screen. Adjust composition, exposure and lighting as needed.