Haha Chris! If we were doing that I would tell em 92A1 and he could thank me later! No wars though. I'm not even familiar with the cz, (I just swear by the Beretta!)
Any who... if your not carrying and your strictly range and home defense why bother with another glock? (Not dissing glock, you glock lovers!, just making a point)
The only attachment your gonna want is the spare mag...
You've got the glock and its at home I'm assuming. Grab the p99 and get familiar with it, after some time you'll be great with two different styles of handguns.
Unless your strictly planning on buying glocks the rest of your life, switch it up. Im a Beretta guy, but I realize there are all sorts of types of guns for all sorts of types of reasons. Again though, ultimately its up to you, don't let another persons opinion weigh down on what YOU WANT/NEED