Are you as tall as you can go with the cage?
Soft tops on blazers are a bit weird the hoops for the top are the big problem not the overall I interior room.
When your passengers are close to the cage sometimes the best answer is harnesses. Keeps em from bumping around

1) for adequate headroom, the front seats will have to be bolted flush to the floor. Disappointing but livable. Makes me feel short like an 8 yr old driving my dads truck.
Looks good! Can you just make the roof cross bracing raised up a bit?