the bear II wrote:
Quikest, cheapest and best is the Tennis ball on a string hung from the ceiling.
When it hits the windshield ......STOP !
Mount a concrete tire stop like they have in parking lots to the floor of the garage. Cheap version is a 6X6 piece of wood - use 1/2" X 10" countersunk lag bolts with expansion inserts into the floor to hold it in place.
X2 on the tennis ball. Park the vehicle where it belongs, hang a string from the ceiling to the windshield (and down a bit), then adjust from the ground after you poke the string thru the ball. We have two of these in the garage and they work flawlessly.