Corner Weighting ideas

As you know the Hiace has adjustable front torsion bars with fixed coil/cart springs on the back.

On my Hiace the torsion bar adjusters are set slightly differently which can only mean 1 of 2 things:

1) It's been corner weighted and the setting is correct
or
2) It's wrong (unbalanced).

So I've been investigating how to corner weight the van. Corner weighting is a system where you place the car on 4 scales and make sure the diagonal sum is equal - i.e. FL+RR = FR+RL.

Torsioning up one wheel then increases the weight borne by that diagonal.

Anyway a decent set of these scales is just under £1000, which I'm not quite ready to spend yet. There appears to be no handy local garage with them either.
The problem is that the front weighs IIRC 1050kg, which means a weight of 525kg per front wheel. This means to do it cheaply you need 3 x 180kg bathroom scales per side. Bathroom scales top out at 250kg sadly, people are just too light.

So rather than buying 6 scales I came up with a cunning plan that would work if one could assume that/make the van equally weighted from left to right. This is a false assumption but one that allows this idea to work, perhaps I'll figure out a way to balance it later. The plan is then to set the van onto a dead level surface and then slowly jack up the middle of the rear diff. The idea is that the first rear tyre to leave the deck indicates too much weight on that side's front tyre. The idea then would be to adjust the torsion pressure on both sides until the back tyres touch the deck at exactly the same time.

This then requires no scales at all and should get it right - assuming a level deck and a balanced van (left-right balance).
A laser level solves the first requirement, so how to balance the van left-to-right? I can think of to change the balance is the swivel seats's position and loading up the van on one side of the other with spare stuff to balance it.

The big issue is how to check if the left-right balance of the van is equal.
Perhaps pivoting on the front crossmember plus the rear diff?
Any ideas?

ETA: A variation of this idea appears to be the Mumford beam:
http://tentenths.com/forum/showpost.php?s=e2ab546d38960f850527bc8d01110093&p=2271175&postcount=5

Mine is also set differently left and right. I blame it on the old torsion bars not going down equally over time. I have more weight on the left if I needed to guess, and that is also where the driver has been when driven, but the right torsion bar needed more cranking and thus seems to be worn out more. I would rather replace them at one point. (that would be at least 500 euro for the parts)

But yes, the corner weighing would still be good.

There are good garages that do corner weighting mostly for high performance race cars one in Sheffield does a good job.

Race cars are usually setup as they have coil-overs etc that allow precise setup. Effectively we have the same as that on the front, the back we just have to hope is level.

The first check I've decided is to jack up on the diff slightly and see if the rear tyres lift evenly, I need to level up the ramp perfectly first though! Most of the static and braking weight is on the fronts anyway so I think that's a good enough check for me. Given our rear springs are fixed I suspect it's not too far out but I'm curious now!

Could be unequal wear or the torsion rods, they are 20 years old now

Yes that is what I'm thinking.