Hello, I am confused and need help. I have an NX8 2.5-20 that I love. Problem is it is on a very heavy block 2esk build and the parallax is very fine. When I am standing and shooting I don't want to adjust the parallax between targets if I don't need to. I'd rather be able to stand and shoot like it's an ACOG if I can.  

When I max out the magnification the parallax is definitely more obvious than at lower settings. I understand the truest test is to move my head up and down to see if the reticle moves as opposed to how in focus both the reticle and sight picture are. But as a good rule of thumb, if I set the parallax to infinity and run it at lower magnifications will this have a major impact on my accuracy between distances?

How are LPVO's able to accomplish setting parallax at 125 yards yet still be accurate within and beyond that distance?

I'm just looking for a best practice on how to use a parallax adjustment so I can be fast between targets and then fine tune the parallax when I am posted up and have the time to make accuracy really count.

I'm still saving to finish it with a piggyback red dot, which I know will help a lot but how do the pros use parallax?

Depending how far away you are parallax can have an effect and it increases as the distance increases.  It is not a huge effect and someone probably who has more knowledge of the subject than me can give you real numbers.  One way you can negate the parallax issue is consistency getting behind the optic.  Shooting inside 200m it is just not going to be a big deal unless you are really getting behind the optic and have large amounts of scope shadow.