Sight picture and red dot

Hello,

I am hoping that someone could answer two questions for me.

1. I have only put 40 rounds through my CA94 so far. The good news is that I was making a good group with some holes touching. The bad news is that I
was about 4 to 5 inches low. I wasn't too far away, only about 25 yards, and I was using 115 grain round nose 9mm. My point of aim was mid way on a circle
target (about 6 inch diameter). So, should I cover the target with the front post?

2. I want to run a red dot sight. I looked on Google, but got air soft mounts as a result, so does anyone have a good recommendation for a red dot mount?

Thanks, Missourian