Re 4. I think it depends how you interpret. If we have spilt circuit front and rear, each circuit does operate 2 wheels, of which both are on opposite sides. So in essence you ether need a diagonal split, or split across the axle. What you can not do is have a split only across near side and offside is how I would interpreting this. Also from the IVA perspective I believe that testers do have additional guidance against specific cars. (I think this also includes the solid copper rear brake pipe as acceptable)