So for Justin's cage, it doesn't fit perfectly, it could definitely be better. The part of the main hoop that is above the harness bar and goes into the horizontal part at the roof isn't that far away, but it could be closer. But it's a compromise, you could have a cage that fits up against all the body panels, but then you spend as much time cutting parts out and welding them back in so you can weld all around the tubes that it ends up being not worth it. I also think that I was making the distance between the center of the two top bends on the main hoop a little closer to each other than I do now when I did that cage.
But it's strong, it fits pretty well and there's a ton of room for the driver, which I think it more important than having a tube 1/2" closer to the body. But also, my cages are always evolving, I am always finding different and better ways to do things, to make things fit better, to make them easier to weld, etc. I'm still very happy with how Justin's cage came out, the main hoop could be a little tighter and I could've done something a little different with the bends in the halo, but that's just nitpicking. You hardly even notice the cage when you're driving the car or even getting in and out. It's not intrusive or in the way, but you know it's there and strong.
I tend to leave a little room around points that are going to be in tight corners if possible. If you can't get a good weld all the way around the tube, then there is no point of even putting it there. On my cages, it's mostly the lower points that are tucked a little in. So the bottom of the main hoop and bottom of the a-pillar bars are pushed a little away from the wall so that I can get in there and make sure everything is strong. But I have been pushing the middle bend closer to the body than before. So now I put the location where the harness bar bolts up and where the dash bar goes across against the walls of the chassis.
With some of the cages I've seen that have bars with "perfect" fitment, I've noticed some that aren't even welded all the way around. Or there is some half-assed, make it look like it's welded crap going on. I just don't trust stuff like that.
It's definitely possible to get perfect fitment, but it depends on your process and how much time you really want to put into it. Cutting the roof off is one of the things that I would love to start doing, but people won't want to pay for it. There are also some other tricks that could be done to get bars in tighter spots, but again, it would get expensive labor wise. I wish I could have someone walk in and give me a blank check and tell me to hide the cage in the unibody. It would be awesome, but it's not going to happen.
As for the holes in the floor. I don't like them. It's not that it isn't a way to do it, but I just have some problems with it. It goes back to the way I design my cages. I'm real anal about everything being where I want it to and being symmetric, so I do things a little differently.
But if you cut holes, it's fine, just make sure to seal underneath the car after you weld the base plates on. And put a little thought into the base plates, but that goes for all cages. Just one flat pieces of metal welded to the thin metal of the floor isn't going to help spread the load as well as a single piece of metal with bends and welded to both horizontal and vertical parts of the chassis. You don't have to go crazy with it, but at least a little something more in good in most spots.
But I have a ton of pics in my gallery of the cages that I've done.
TIP Roll Cages
I haven't posted up some of the more recent work, but hopefully I'll make some more progress on my brother's supra soon and then I'll put pics of that up.