If your matches have 300 yard plate racks (Lucky people if you have matches with that kind of room) you will need a 300 yard zero and then know your hold overs closer.
If on the other hand your matches never extend past 200 yards and most of your stuff is up close and personal, a 200 yard zero works great. We primarily shoot the IDPA target around here, and the 200 yard zero means hold 2" low at point blank, "on" at 50 yards, around 2" high at 100 yards, and "On" again at 200 yards. One time, I fired the NY State USPSA rifle match with 3 shots at 330 m on strobe light equipped targets. I used my 200 yard zero, and I just held the top of the target for those very few long ones. Worked perfect.
Billski