Not using a front rack, my light is closer to the fork than you are talking about. For that reason I probably have more shadow than I would otherwise have. I use a regular handlebar bag on a second stem, not a rack to mount it.

I get a small shadow that is within maybe 8 to 10 feet of the bike off to the left side, does not bother me. My light lands on the ground where I will be going, that is all I need to really see. I bent the metal light bracket to get the light up higher. In my case I also used the optional extra long mounting bracket instead of the stock one that came with the light.

There is a 90 degree sharp left turn on a bike path that I sometimes ride, the shadow blocks some of that turn when I am going slowly up to a few feet of that location, but that is the only time that I have noticed any issue.

Since the photo was taken, I have rewired it to get rid of some of the excess wire. Disregard some of the excess wiring.