I'm not passing judgment on your cage, the quality of your welds, or even its design. That's not my line of work.
I will warn you that this would appear to be an unconventional design when it comes to road racing cages. None of the AutoPower cages seem to be designed like this, none of the SpecMiata cages are designed like this, and I've not seen a SpecE30 cage designed like this either. It may be that your design is perfectly fine, maybe even better than all the other designs out there.
But be prepared that you may get an argument about this when you go through tech, and tech may decide that this design isn't safe because it doesn't look like all the other cages out there. Again, I'm not passing judgment. But I've seen how things go when somebody tries something different and then has to submit it through safety tech, and it's often not pretty.
(FWIW, Page 19 of the Lefthander Chassis catalog shows a cage done in a similar way, at least for the halo bar)
Personally, I'd design it to look and function like all the other safety cages out there and avoid the hassle and the chance that I get to rebuild my cage on the spot to meet whatever the tech inspectors want, especially since the standard cages seem to do a pretty good job in a rollover. You might want to think about getting John at Evil Genius Racing in West Sacramento to take a look at your cage and bless it, he's a NASA Safety Inspector and his blessing might help you down the road if things get ugly at tech.
But this is your ride, and I wish you luck. Just be prepared to make your argument. And don't forget your main hoop diagonal.
Pat Mulry, TARP Racing #67
Mandatory disclaimer: all opinions expressed are mine alone & not those of 24HOL, its mgmt, sponsors, etc.