I have a Comp Tac International
I feel your pain, the CZ 75 is not supported very well in the aftermarket. I use a Comp Tac International with my CZ 75b in IDPA, and it's a pretty nice rig. The holster comes with the mount you want installed (belt carry on mine) and the other options (paddle and drop/offset) in separate bag. You can change between them if you want, but like someone said about paddles suck for competition and drop/offset is not IDPA legal.
On mag carriers i.e. mag holsters, I'm suffering through the "buy cheap, cry twice..." alignment because I've tried to cheap out twice. The first was cloth carriers that dropped my rear mag after I got rid of the cover flaps, and the second is a SigTac (?) paddle double carrier that flops around on my belt. If you like the pistol and are going to keep it, get quality mag holsters from Comp Tac, BladeTech or similar.