For small game at 20 yards the 1-4X20 is fine... for shooting paper at 50 yards it is seriously handicapped. A couple thoughts; the bolt throw on your CZ makes the straight tube scope pointless, with the taller ring you might as well use a scope of 28mm+... a straight tube scope mounted in medium rings hardly looks good to my eye.
On my Ruger RSI's I have the Leupold VX-2 3-9X33mm EFR, it is a really nice balance of wide field of view with enough magnification for tiny groups at 50 yards. It is also quite light and compact.
CZ options with VX-2 3-9X40 & VX-2 4-12X40... you will notice that the longer scope on the FS comes into conflict with the rear sight, necessitating higher rings... shorter tube length scopes avoid this issue;
On my Ruger RSI's I have the Leupold VX-2 3-9X33mm EFR, it is a really nice balance of wide field of view with enough magnification for tiny groups at 50 yards. It is also quite light and compact.

CZ options with VX-2 3-9X40 & VX-2 4-12X40... you will notice that the longer scope on the FS comes into conflict with the rear sight, necessitating higher rings... shorter tube length scopes avoid this issue;
