It's not too hard to install once you stop getting the wrong instructions.
Apparently not all of these rifles have the set screw retainer on the selector.
So here's the way to take your old one out:
1) remove set screw if applicable. It's small and metric and mine was in really tight.
2) make sure the selector is in the right position (safe, IIRC) so you can push it through from the left. If the selector is not in the right position the thing that comes off the trigger is in a notch on the selector. This prevents the selector from being pushed through.
3) push and wiggle it to get it out. The spring that keeps it in safe/fire positions my need to be pushed down to help it out. It's the flat spring on the bottom right side of the receiver.
Install the new one in reverse order. You may need to depress the spring again and ensure the trigger thingy doesn't interfere with the end or the notch on the selector.
To install the left side lever:
1) figure out how you want it indexed.
2) use a small nail or pin punch to line up the holes
3) drive the roll pin in. As it goes in, it will push the nail out the other side. You don't need a lot of force to push the roll pin in. Too much will bend the end of the selector shaft. I used a small brass hammer.
Note that the rotation of the safety is reversed. Push forward on the right side to fire. I indexed mine so that the left side lever sits level when on safe. My thumb rides on top of it and pushes it down/forward to fire. This works very nicely. Use your trigger finger to reapply the safety by pulling it down/rearward.
The pin on the left side lever is quite small. It's easy to lose when you drop it. The shaft isn't splined so you have to line up the holes manually to drive the pin in. I found a small finishing nail through the opposite side to the pin helpful in lining them up. With the nail in place, tap the pin in from the other side. It's way easier than trying to eyeball the hole line up.
I'm considering cutting the lever off the right side so the selector is only on the left. I need to shoot it a bit to see if I want to do that.
I can see that if you own multiple VZs and want to use this safety you will need to convert all of your rifles to this configuration. Otherwise you'll have guns that have safeties that work in opposite directions. Not good.
Set screw is in the circle:
As has been mentioned this is a development version, not the upcoming final version.
The selector will not rotate a full 90 degrees unless you modify it. The tail on the selector will be changed to address this on the production version.
Before, safety on:
After a bit of Dremel work, safety on:
Left side selector, safety on:
Ignore the tool marks on the left side lever. I did that, they didn't come that way from NEA.
Safety off:
