Not sure how that would be unsafe, though it's of course possible, as the original seatbelts are also mounted to the bulkhead? And there the impact weight is only distributed through one point, whereas with my setup the load is distributed through 2 points. I agree it's less than optimal, and a proper full cage is being looked at atm, but if your leaving your interior intact, not many other options. I am also not sold on the bulkhead being weak, as the factory roll hoops are attached to it.
I think Ian also had some pics of the way he did it, same as mine, might be easier to chase those up as mine is hybernating under 3 huge tarps/covers atm.
I also have to add, if you think it's unsafe, please don't do it. Mine is a little different anyways as where my roll bar is attached into the bulkhead, it's also welded to the chassis. On the subject of rollbars, not sure why everyone is attaching the bars using the rear shock mounts as an anchor point. Pretty unsafe too, but my bar builder says that if you do have a roll over, the wheels are 90% where the car will impact, which will directly force/distort the cage/bar probably nicely into the back of your chair. (Read, into you)
Ti, yours being an exception, as I think your other rollbar on your coupe was one of the only ones I've seen not tied into the shock mount.
I guess there are pro's and cons to everything.