It is my experience that only Remington ammunition, the bucket o crap variety, causes problems in my CZ 452. It shoots as well as can be expected but it does not consistently eject. The same ammunition caused the same problem in my Mossberg 142. Neither gun has ever had an ejection issue with any other ammunition. Both guns immediately stopped having problems when I switched ammunition.
Having said that, I am not sure what you are "testing"? If you are concerned about accuracy and repeatability, the CZ's inherent accuracy will not overcome the tendency of some ammunition to shoot without adequate consistency. Those bucket o crap Rem rounds (if they consistently) ejected were a very poor target load. If you shot a few hundred rounds, you could guarantee that at least some number of them would stray from the point of aim. This behavior would rule them out for any competitive use. You will probably find that to be true of most of the run of the mill ammunition that is not match grade. The gun cannot overcome sloppy manufacturing.
I exclusively use Wolf Match Extra for target (50 feet and 100 yard). I also use it for hunting. I find that it is very consistent. It also seems to be very predictable. I have had two "no fires" in the last 3,000 plus rounds. Both of these fired when I rotated them and re-shot them. The primer was apparently not consistently coating the shell.
SK, Lapua, Eley, Wolf....these are generally accepted and shoot well in the CZ. My only complaint about the Wolf is the amount of wax I find on some of the rounds.
For an alternative and bang for the buck that CZ's like, try Federal Automatch.
With respect to CZ triggers...they are adjustable and can be adjusted to an acceptable hunting pull. To reach a target ready trigger you will either need to swap to Timney or do a trigger job on your own. I have my 452 set to a bit under one pound using the factory trigger. I did not do any filing, stoning or machining to achive that. A Timney will not fit this model stock without cutting wood....