RE: What kind of Chronograph?
Either will work, I have owned both. It is hard to beat the Chrony F-1 model for simplicity.
If yourshooting outside you will have to watch your lighting or else you will get some wacky readings. In addition, being that it is for "public use" and possibly could get a lot of traffic, I might put a partition in front of it to protect it from any "accidents".