Thanks for the info! I have never seen RS product but it looks like a good setup... not cheap though at roughly $350 for the mounts. Does the lower come with the mounting hardware for securing it to the side of the receiver?
I can't clearly see in the picture but is there enough space between the dust cover and the upper mount to use the iron sights?
An Acog sure would be nice to mount on her but for the price they are going for I'll have to sit around and wait for CTCS to more prims in.
To answer your iron sight question....it depends. The RS mounts very very low, thats basically what you pay for. I have a Browe BCO and zhukov stock on my NR vz58, and the eye relief/eye box issues on these ACOG type prisms basically dont exist. I dont need a riser and set the distance to my eye perfectly. If I QD the optic off, I can see use my irons just fine. (Some people think that you cant use the irons on these with an inline stock, thats nonsense. If you stand in an isoscles stance, its fine. If you have a bladed weaver style stance than youre doing it wrong and I cant help you

)
Some of those scopes that use the ACOG mounting system have a little peep hole through the bottom of the scope, because it was originally designed to mount on an m16 carry handle. So the answer is "maybe", but assume that you cant.
You still need a side dovetail to attach to your receiver, but thats universally required wether you get an RS mount, a russian one, or an all in one scope and mount like a PSO. CSA built rifles have the receiver taps, Cz858s do not. CSA makes those dovetails, and RS regulate has been promising a lighter weight version for a while but its been pushed back.
If you need a dovetail, I may be able to help you with one if I can find it. PM me.
Now, this information applies to *scopes*, as in magnified optics. If you want to mount a red dot, or similar there are 3 options. Two of which allow co witness.
The first is an NEA piston cover/upper handguard. I have them on all of my vz58s even though I dont mount anything on them. Why? They were on sale for 40 bucks a few months ago and they are half the weight of the standard piston cover. They are also, to my knowledge *the only* upper handguard rail that sits low enough to allow a T1 sized dot to cowitness with the leaf sights.
The second is the RS lower, with the T1 upper. That will also co witness (and QD, return to zero).
The third option, which is cheapest but my least preferred is the CSA side rail mount. It sits somewhat low, but will block your irons. You will not have cowitness. It has a picstinny rail on top, and you *can* mount a PA prism on it...and it will work as long as you have an inline stock or a riser on a slanted one....but that contraption starts adding weight. I used it until I upgraded to the RS mount and Im glad I did. I cant decide if its worth the money *for you*, but it was to me.
Another direction, is a BP-02 "low mount". You can get these fairly cheap if you look around. Whats great, is that due to the fact that a vz58 receiver/top cover is a full inch or more shorter than an AK, you will see your sights from below the mount. You will have only a chinweld, but if its a non parralax/eyerelief optic like a red dot or eotech then that can be acceptable. Also, if youre using an optic that will never co witness on these guns no matter what you do (like an Eotech) then being able to see your sights from below is a good second fiddle.
In my experience, if you set the tension correctly and loctite everything that youre supposed to, the RS, CSA and BP-02 mounts will all return to zero if you take them off and (kick them around) put them back on. I like that. Makes transportation easier and lets you play around with good old iron sights if nothing else.