I don't have an ambi to be able to model it for one - so not for the first run at least. I have been looking at them however.
No one makes an ambi for the CSA guns anymore, least since NEA made their last run at least 4 years ago now...
I have a spare short throw rear to fire I'm happy to send you for testing, but even w/ those the Century guns need a bit of material removed around the pin hole on the right side of receiver (since higher shelf than Czech version) to be able to run them. In brief, it allows the support thumb to manipulate the safety for righties, like with ARs, Galils, etc... Or if preferring to use trigger finger, the short throw makes that action much quicker as well.
It truly is a major improvement to ergos for this weapon system. One of those things where you don't know what you're missing until you try it...
My recommendation however would be to design something integral -- I'd imagine more of a longer lever like a galil safety would be needed w/ a side rail, don't know that you could use standard. Thinking outloud and giving IP release, open sourcing -- I think you could potentially even do something as simple as drilling and tapping standard safeties (be it CSA version or milsurp) and allowing a longer lever install (to run w/ side rail) or a mirror of standard safety lever if using w/o. And then just attach the levers w/ allen key screws.
A major negative on the aftermarket ambi safeties is that both sides have to be properly installed to properly function... Each side ties into a different side of the receiver and then the two pieces are secured together internally w/ allen screw. So w/ tapping, you'd maintain the overall reliability of the OE safety and if losing the "ambi" side lever due to the screw coming loose, you're safety is still function -- in the AR world, quite similar of comparisons between the Knights and BAD safeties...