I don't have a CZ, but I just put an EGW rail and rings on my new Marlin XT-17. The XT had came with Weaver bases and I mounted a Bushnell Banner 4-12x40 on it with high Weaver rings. Unfortunately, the eye relief on the scope is fairly short and the XT receiver is very long and I couldn't practically use the scope over 6x. The EGW rail allowed me to mounted the scope about 1.75" closer compared to the Weaver mounts. I did have to cut the front of the rail down about .75" to achieve this. The front of rail interfered with the objective bell of the scope. I did also end up with the a slight interference between the bolt handle and the scope ring, but not enough to affect the operation, some paint has worn of the bolt handle and a I should file a corner of the scope ring. I'd only need to take .010" to .015" off the corner of the ring to clean it up. I would say the scope ended up about 3/16" higher on the rail compared to the Weaver bases, I don't really feel it's a problem, and I'm now looking at putting on a scope with a 50mm objective, which I should have the clearance for.
I cut the rail off with a hacksaw, and for aluminium, the rail is pretty hard. I would say its comparable to a structural steel. The coating is also noticeably harder then the aluminium itself. I'm pretty happy with it.
I ordered the rail and rings directly from EGW. The only problem I had was finding an internet browser that would load the province select menu on their website (used Chrome on the PC, nothing would work on the iPad and IE on the PC wouldn't load the menu). Got the order in week, ordered Monday, shipped Tuesday, received the following Monday and Easter Long weekend happened in the middle.