1. Make sure you get a super nova.
2. Since you are lane security, I would suggest you look into a mini razor or a CD as your second weapon.
( you can install a nova missle but, I dont believe you can even fire those simultaneousm though it has an ammo)
3. As for the rest of the guns, buy the heaviest possible ones you can hit with. One advantage of a Bomber is that it has a massive power plant and take take the strain.