I am unfamiliar with arena/host variables that may be in place to change enemy distances displayed in detail (rather than estimated within 100 yards as it is) out to X distance, but I believe what you are looking for is under the arena settup/settings. Hopefuly someone who is familiar in this area will stop by.
In the MAs it is set by/on the host/server and unadjustable by players (unless it be exploited. You can look up the variables and see what they are - you just can't change them unless you work for HTCs).
Off the top of my head, for training and practicing purposes, you can disable KS (kill shooter) and enable FF (friendly fire) offline or in a custom arena, shoot at a friendly AI or friendly player willing to help you. You could also go to the TA and find someone to help you and stay on the same country (I believe TA defaults are KS is disabled and FF is turned down to only inflict a minute fraction of the actual damage that would of happened)
Edit: Try and ask the more seasoned AvA staff members who have experience setting up and running weekly events the AvA arena - I suspect they are familiar and know about where these icon settings are at in the arena settup, and what if any limitations exist with them.