I found out the with Heading-Hold enable if you want to change heading its very easy by using Trim. Not by holding it.
A way to test it is by resetting the PVI-800, enable all the auto pilots, change heading, press and release trim every time you change heading, and you will notice in the HUD it will create an indication of your new heading (like the waypoint dot). This helps a lot believe me, it took time for me to notice it but it works really good especially if you are applying rudder. Don't trim while you are applying rudder. Apply first rudder center your joy then trim quickly to your new heading.
It make flying BS smooth and easy without fighting the auto pilots.