As a speed steel competitor, for reflex red dots (window instead of tube) I put it as far forward on the receiver as possible regardless if it is a TruGlo, C-More, or what. And as low as possible. I have tried risers but keep going back to flush because when I raise the gun from ready to the first shot I find it puts the rifle right on my cheek every time with the dot centered which does not happen 100% when placed higher. If I was to use it higher I would want a cheek riser on the stock. With tube sights (AimPoint, Burris, Ultradot) the tube actually sits lower on the receiver compared to a reflex window so in that case I do use a riser to get the window a little higher. I also place it a little more to the rear than a reflex sight.