Well I'm back from 10 days of traveling for work, and got straight to caging to try and make up lost time.
My plan is to fit the front seats, and a third center seat will happen if possible but is not a priority like the front two obviously. With my experience from my 4500 land cruiser, I decided the best way to run the B pillars was to do outriggers like the front. This keeps the B pillars a lot more simple and straighter than coming straight up off the frame, while also netting more clearance for the seat and helmet.
I decided not to plate the frame here for a few reasons. First of all these outriggers aren't nearly as long as the front ones; secondly in the event the B pillar gets loaded there are a lot more paths for the forces to distribute where as the A pillar really only has itself to dump load into; and third I didn't have to cut off parts of the frame right off the bat so in no way weakened it prior to welding to it. And of course these in their finally form will have additional bracing/gussets to the frame.
Having already mocked up where I thought the driver's seat should go (which controlled the outrigger position), it was time to start the B pillar.
This was my first attempt, I bent the tube towards the bottom instead of towards the top thinking it wouldn't turn out this low. My goal initially was have the bend at shoulder height and kind of follow the contour of the body/seat. After talking to Matt and Connor I redid it.
Attempt #2 is a lot better. Because the seat is angled back at 15-20deg inherently, there is a lot of room between the base of the seat and the actual headrest which makes things tricky since you want room for the seat but also want to be tight to it to give room elsewhere, especially in the event of a possible 3rd seat. Additionally I am not sure what exact position Matt will prefer, so the more adjustment I can keep the better. To compensate for this I decided to angle the B pillar backward so it's parallel with the back of the seat. This gains room at the base of the B pillar by about 7", which means the B pillar is mounted further forward instead of about 1/3 way into the rear door area. There's a side photo later detailing this more.
Because of this, if I add a rear door bar then I will have a long diagonal section under the door bar to help brace the B pillar, along with tube gussets at the top. If there is no door bar (which essentially would only be there for a rear passenger) then I will just run a big diagonal that will serve as the C pillar, this is the strongest/best method imo but doesn't allow for easy ingress/egress from the rear.
The B pillars are tacked at the bottom, and are notched for the halo/A pillar pass through at the top. With both B pillars in, I had to assume they were in the right spot if I wanted to keep moving since everything goes through the B pillars. I started with the front door bars.
The doors will need to be slightly clearanced since they rub, but I'm really happy with how they turned out and they'll give Matt and Connor maximum room up front. I tied into the lower A pillar an inch below the dash bar, and then have three bends of 10/10/15 going back and then tying into the B pillar. The body B pillar will be gusseted into the door bars later on, and I already prepped the body to be welded.
You can see how much room is allowed for the front passengers, although the B pillar looks pretty far back there is actually quite a bit of room to still get through the rear doors. Just sitting in the seat and all the way back I can't fully depress the gas pedal and I'm 6ft tall. The seats allow for ~8" of adjustment total.
So that wraps today up. Not too shabby for a few hours of work. My goal with this is to add lower door bars, and then have seat bars that come off those horizontally and then little tabs off those bars that the seats mount too. So the seat mounts will be at least 2" off the floor. I also plan to scoot the seats as far inward as I comfortably can, this will allow for additional helmet clearance with the halo. My goal is to have at least the driver seat and steering wheel fully mocked up by Wednesday night.