A word of caution. Spotlighting deer not a good thing to do in some areas. Poachers and and horn hunters in some areas use this technique to find and kill trophy (and meat) deer. We have them in our area, riding backroads and around large fields spotting and killing deer.
State has wildlife officers out trying to stop this but they have huge areas (around our part of the state) to patrol and enforce. There are laws here that prohibit even spotlighting. They are defined as harassing wild life and some judges take a dim view of this.
I don't know the rules in other states, but not a good idea here