Another option (after discussion with Jamil Ustaad - who speaks highly of the setup in Suhaib Bhai's FJ, btw) for the anti-roll apparatus that I'm also considering, consists of four anti-roll bars.
The first, is in the general line of the windscreen, and is bolted to the belly sliders, after passing through the floor of the cabin. This connects the roll bar to the frame, permanently. The second bar, is at the pillar between front and rear doors. This, too, passes through the floor of the cabin and connects to the belly sliders. The third bar will be constructed at the rear of the cabin, and will similarly be connected to the frame, by being passed through the floor of the cabin. These three roll bars, will form the "inner cabin cage". Of course, rubber washers and silicon joints will seal their exit points from the cabin to the frame. The fourth bar, is part of the jangla built at the rear, on which the tyre will be mounted at a raked angle.
All three bars "inner cabin" bars will be affixed at an equal height, so that the weight distribution in case of a spill, is divided equally amongst them. They will be connected via cross-members, so as to reinforce them. 3 to 3.5 inch pipe will be used of a sootar gauge. The fourth bar, won't be connected to the inner three, but will be the same height as them, and will be anchored at four points to the frame, by means of an angled bar. Theoretically speaking, this enjoins the entire roll cage (all four bars) to the strongest part of the vehicle - the chassis / frame - at ALL points. Again, theoretically speaking at least...it SHOULD provide the maximum strength, with a minimum of weight.
I really need to photoshop / sketch this arrangement out, for it to be entirely comprehensible!