personally i would say have a custom cage built. Yes they are more expensive but everycar is different and normally bolt in cages have lots of leiway. Custom cage will get you that baller "a game" fitment. It will also be built to your requirements and tolerances. I wouldnt have chimed in but work at a roll cage metal fab shop. Seeing how it is done and how well fitting a good cage is blows a bolt in out of the water.
Unique Fabrication
Yeah custom shit is more but with something like a cage you can't really put a price on safety.