Headlight aiming question

So I think that I may need to adjust my headlight. It seems that at 35-40 miles an hour I am riding faster then the light hits the ground for the 2 second rule. I have read in multiple places that you should have the bike on a level ground 25 ft from a wall. That is where I have my issue. I have quite a slanted driveway, so I have maybe 10 ft in front of the bike when parked in the garage on a level surface. Is there another way to adjust the headlight with this short of space. My worry is that if I take it to a parking lot to use a wall, I may screw it up worse and then have to ride it home like that. I would rather do this in the safety of my garage. Thanks