full roll cage
I would think that you would want to match factory roll bar specs so you could drill the mounting holes to connect the frames around the doors for the top and so that it would sit flush through the middle. Then you would have to look into how you want to handle the B-pillar since its the major structure there. Sorry wish I could help more but my custom cage build is so far away its just a dream at this point. Best of luck and hopefully this helped a little bit.
Yes I agree with all of your points. I built a full cage on my old TJ but the b pillar on the 4 door adds a new wrinkle. I have also heard of some going to the floor through the dash (on the A pillar) and some have welded directly to the tub at the windshield frame seal.


