Here are some dimensions (please note that these are close, not exact):
10": width of lens on 10" E series
11": width of front frame on 10" E series
2 7/8": height of D2
2 7/8": approx space between upper and lower Stealth bars. I will need to remove a D2 to see if it fits between the bars on my rack.
3 1/8": Width of D2
12 1/2" mounting width (at bar) of 10" E series. A 6" E series would be 8 1/2" wide at mounting point
7 1/4": Width of Stealth between outer bend (upper rail) and welds. A 6" E series, with a mounting width of 8 1/2" will NOT fit if mounted to the upper bar though it may if mounted to the lower bar
17": width of center section
3 1/2": approx depth of 10" E series
3": approx depth of D2, excluding bracket
3/8": additional width of E series lamp between frame and mounting point
7/8": width (widest point) of E series mounting bracket