What is your specific issue with the gas system?
The 16" version is a heavier barrel, as a result the profile will be thicker than that of the shorter gas system and will result in the front heavy rifle you don't want. A thin hollow alum tube that can be un threaded from the front of the rifle pictured is still lighter than the heavier profile barrel of a converted 16" rifle
Pretty confident that CZ did extensive testing before deciding that there would be a different gas system on the "short" rifles vs the "long" rifles. Logically they must have saw something that made them want a different gas system on each. What that was I dont know - but there was / is a reason.
Will the short gas system work on one of the longer converted rifles - it certainly seems like that is the case based on your feedback (and others). I sense you are more than happy with your choice and I respect that. As I mentioned perviously I feel like I want the longer gas system as that was the system the manufacturer chose / designed into their rifles in the longer configuration.
I am still undecided with what to do with my order but fortunately I have other rifles to fill the role in the meantime.