To get a perfect IV Pokemon, between both parents there needs to be perfect IVs.
You don't want the perfect Sp. Atk stat, so I left it out. What I am saying, is that the mother's imperfect IVs need to be filled in by the father, and vice versa. Once you've done that, it all remains on luck as to if you'll get a perfect offspring.
And it won't really 'mix up' the IVs. Like, the Defense IV from the mother/father will be given to the offspring as the Defense IV. Like, it would be:
Oh! He/She's got your eyes.
Oh! He/She's got your feet.
Oh! He/She's got your Defense IV.
So, if that's what you're thinking, you're wrong. Just sayin'. :3
Hope I helped. :)