Do we need to have 2 gates at the start to trigger the timer, or is there a quick start box that can be used instead with only 2 gates on the other end?

To be clear we define a "gate " as being a pair of tripods, one with a reflector and one with the Timing Sensor itself.

You can either use a single gate at the start, on tripods, or you can use an UNO single beam gate in "Ground" mode. 

This gate sits on the ground on magnetic base plates for stability (both gate and reflector). In the is way you can trigger timing with foot or hand lift.