[FG28_Kodiak]

GamePlay.gpHUDLogCenter(null, "Only two seconds visible", new object[]{}, 2);

last Argument in example: time in seconds (double)

ups missunderstood the question:

you must place the messages if used in OnTickGame in a if clause example:

public override void OnTickGame()
    {
        base.OnTickGame();

        if (Time.tickCounter() % 300 == 0) // every 10 sec.
        {
             // your code here
        }
    }

a tick is 1/30 sec.