First let me say that I was predominantly a coiler Rover guy located in Northern California in the US. I am posting this for a non computer savy friend as I have not YET

joined the ranks of Bezel owners.
My friend is running into the issue of spring replacement choices. There are plenty of good traditional brands and even a couple reputable custom manufacturers of traditional multi-leafs available. But the conflict relates to his interest in parabolic springs. Hence directing this question overseas.
Vehicle: 1974 bj40, 2h, 5spd (h55f if i recall correctly), fj60 axles, 9.00-16 STA Superlug. It has a MAF front bumper with warn 8274-50, MAF rear twin swing bumper(spare, 2x diesel can, 1x water can).
It currently has an old lift of unknown manufacture.
I do not happen to have the front and rear axle weights, (loaded or unloaded for trips).
This is both a daily driver and trail vehicle.
He is interested in possibly extending the wheelbase to 96-100 inches using fj60/custom springs OR using parabolic springs.
For anyone running, or who has run parabolic springs have you approached this kind of load and what were your experiences?
Thank you in advance. Quest
