Re: use of cover. It's recommended NOT to be so close to cover and DEFINITELY don't stick your gun beyond "the wall" as you don't know what could be on the other side to take your gun or rap you on the hands to make you drop the gun. This also affords you the disadvantage of not being able to use the angles provided by cover so you don't expose yourself to more than one "bad guy" at a time. Shoot one bad guy, then adjust your feet to keep cover while you search to engage the next bad guy. IDPA isn't training, it's a game, but you can use it to practice good techniques even though your times may suffer a little for it. You can also do it "both ways" but remember that you often fight as you train, so make sure you have proper training in addition to "playing the game."