actually, he should just stick to COD. its much safer in there, and the guns are wicked sweet.Are we talking about video games or real life now?
If you "akimbo" them then it is in a video game. If you "dual weild" them then you will likely have little control of either of the weapons.
You should get a .22 and get very good with it. Then work your way up to much stronger weapons. Using something like a ps90 means that ammo will be expensive, which in turns means you will shoot less. Ultimately doing you a disservice.