like the other guys said, if cheaper practice ammo is a concern and you are comfortable with it go ahead, 11 rounds of 9 ought to do the job
BUT, unless you can't get a hold of real mags (instead of those cheasy plastic based politico engineered 10 rounders like the cz75 comes with) wouldn't 15 or more be better for just in case? or wouldn't ten bigger rounds be better?
i know about all the marshall and sandow and the fackler numbers but when i look and hold a 9mm round vs a 45 round the cromagnon in me says "use big club to kill big dinosaur"
being able to get two hicaps with my cz75 was the straw that broke the camel's neck in my decision to get one, if i had been limited to ten rounders in that gun i would have gotten the 40auto
there is just something wrong to me to use any tool at less than it's full ability due to some safetycrat's liberoengineering it
if you don't mind shooting 45 for a little more, why not use 11 rounds of it out of a glock21, or cz97? you would be able to be legal in kali with either one