Dont be afraid to shoot low gun. My only advice is to get a gun that fits properly, and practice your mount from the proper low gun position (ISSF).
I started shooting low gun, because that was just the way I shot. I have trouble getting my eyes off the barrell with a pre-mounted gun. I also find a lot of new shooters who premount tend to want to aim the gun, so getting the muzzle down and out of the way is important to allow for the earliest possible aquisition of the target, regardless of a mounted or premounted gun.
Unfortunately there are few good references or videos for low gun shooters, however, the basic rules apply, head on the gun, eye on the bird! And of course foot position is also critical. My advice would be to go to the ISSF website and watch the skeet videos. Pay particular attention to not only where they start the butt of the gun, but where the end of the muzzle is in relation to their eyes. Also note the foot position on each station, and their hold points and how the mount the gun and move to the target in one smooth motion.