Thing torsion bars, what size are they?

[MySUVW]

What size are the Thing torsion bars and will they fit into a standard Bug torsion arm housing? Are the Thing torsion bars larger than the stock Beetle? I am planning on converting my swing axle 1966 Bug to IRS by welding in the IRS pivots, and using Thing torsion bars and spring plates, is everthing interchangable? Or should I just get a 1969 or later Bug pan and install the Thing torsion arms/spring plates in it and then drop my 1966 Bug body on the pan? I am bolting a Thing front end up to the 1966 bug, but I am trying to see what is best to get the rear end up to match the front end. I want to keep everything stock, no cutting, ect. I will be using Thing IRS trailing arms in the rear also. Thanks for any info on this, - Roy
P.S. all Thing parts where taken out of a burned out Thing that caught on fire......plus it had a damaged front end, so I am not ruining a good VW Thing to raise my VW Bug