Patrick
Since you are still in the design stage you might look at the rear cover from an 8.8 Explorer, I like the mounting much better. I can get them for anyone interested for about $35 to $40. I believe with a load your arms would bend at the curve. I'm going to adapt the Locost Roarty plans for the 8.8 IRS. I know it is a Lotus 7 type but the general Idea would be the same.
http://locost7.info/files/suspension...RSAssembly.pdf
