Last year, Beatty Hammond had a similar design; their robot started vertically and dropped down so it was five-feet long.
Picture here.
Their light was mounted so that it was upright while the robot was driving.
As for the obscurity, it really matters how much you plan to have the light obscured. Having a .75" Al bar in front isn't a big deal. Having Aluminum plate surrounding it is. The checklist states "visible from 4 sides of robot" as the requirement here.
Anyway, this is an issue you should contact FIRST with. It would be a disaster to get there thinking you were OK and then having a judge make you remount the whole thing.