This has been covered extensively, just recently. A few other members lifted the rear and wanted to match the front.
On a flat level surface measure from the top of your wheel (assuming it is factory 15" diameter) to the fender lip straight above it. With a stock front end you should be in the ballpart of around 13" to 13.5"
The most you can crank is to about 14". It is safe, the ride will feel about the same and you wont hit your droop stops on the upper control arm with daily driving.
If that adjustment does not look high enough then you should consider ball joint spacers with a differential drop kit.
If you go this route, spray the hell out of the torsion bar adjusting bolts with a penetrating oil. You can spray right inside it's frame bracket through a hole and spray the threads good. Give it a while.
With a 1986 you have a lock nut you need to loosen on the bolt (just follow the bolt head up above the frame, look from the inside. Ensure you break that loose before attempting to adjust. If you are new to torsion bar setups, and are concerned with rust and the age of the bolts I urge you to not do it yourself, have a shop adjust them. A good alignment shop can adjust the bars.
Regarding OME torsion bars - they are just stronger bars that you still "Crank". If you are running a stock bumper there is no need to invest in those bars. You can only crank them as much as the factory ones, the bump stops, cv angles and everything are still the limiting factor. Ball joint spacers are a better route.
I would adjust first, and if it suites your taste then you are done, for free. If that is not enough then implement some ball joint spacers.